
    UNITED STATES of America v. Thomas David STEINER, Appellant.
    No. 14-4628.
    United States Court of Appeals, Third Circuit.
    Argued: Nov. 6, 2015.
    Opinion Filed: March 3, 2016.
    
      Renee Pietropaolo, Esq., [Argued], Office of Federal Public Defender, Pittsburgh, PA, for Appellant Thomas David Steiner.
    Jane M. Dattilo, Esq. [Argued], Rebecca R. Haywood, Esq., Office of United States Attorney, Pittsburgh, PA, for Appellee United States of America.
    BEFORE: FUENTES, JORDAN, and VANASKIE, Circuit Judges.
   OPINION OF THE COURT

FUENTES, Circuit Judge.

During the execution of two separate search warrants at properties that police believed were owned or occupied by defendant Thomas Steiner, police seized, among other things, a sawed-off shotgun, .32 and .38 caliber ammunition, and 12 gauge shotgun ammunition. As a result, Steiner was indicted on two counts for being a felon-in-possession of a firearm and ammunition in violation of 18 U.S.C. § 922(g). Following a 4-day trial, he was convicted on one count of felony-possession of ammunition and sentenced to an 87-month prison term.

During the trial, the government introduced into evidence the fact that a warrant had issued for Steiner’s arrest on an unrelated charge. Steiner appeals, contending that the District Court improperly admitted evidence of the arrest warrant that was unrelated to the offenses he faced at trial. He also argues that the District Court erred by failing to instruct the jury that it was required to reach a unanimous verdict as to each type of ammunition seized. While we conclude that the admission of the unrelated arrest warrant was error, the error was harmless. We also conclude that the District Court did not err when it declined to provide a unanimity instruction. For the reasons that follow, we will affirm the conviction.

I. Background

This case arises from a sting operation. In August 2007, police informant Timothy Stants told Pennsylvania State Trooper Thomas Baumgard that Thomas Steiner, a convicted felon, was staying on his (Stants’) property and was “on the run” from law enforcement. Stants also claimed that Steiner had a sawed-off shotgun, which Steiner had described to him as a “cop killer,” and that Steiner said he would use the gun to avoid being arrested. Stants claimed that the shotgun would be found in a camper on Stants’ property.

Based on Stants’ tip, Baumgard obtained a search warrant for the camper. Before executing the warrant on August 27, 2007, Baumgard paid Stants $100 for his help in securing Steiner’s arrest and told Stants to drive Steiner to a nearby gas station. There, officers would be waiting to arrest Steiner on a warrant that had issued for Steiner’s arrest for failure to appear at a preliminary hearing ¡scheduled that same day, on an unrelated sexual assault charge. Baumgard conducted his search of the camper in the afternoon, just after Stants drove Steiner away to the gas station. He found — among other things— a sawed-off shotgun loaded with six rounds of 12-gauge shotgun ammunition, a wallet containing various documents, all bearing Steiner’s name, and a discharged shotgun shell. Soon after the search, Baumgard ordered Steiner arrested on the warrant issued for his failure to appear at the preliminary hearing earlier that day. At the time of his arrest, Steiner was in Stants’ car at a nearby gas station.

Apparently, there was more to the story than the gun and ammunition found in the camper. Stants also told police that he had seen the missing pieces of the sawed-off shotgun (part of the barrel and stock) at a home that Steiner supposedly owned, located at Meadow Avenue (the “home” or the “Meadow Avenue home”). Based on Stants’ tip, police obtained another search warrant, this time for the home.

Police executed the search warrant for the home on August 29, 2007. When they arrived, they entered the basement of the home, which was in disarray. There, they found a shotgun stock on the bar and a shotgun barrel in the ceiling where a tile was missing. Also, they discovered a hacksaw and pipe wrenches on the basement floor and a single 12-gauge shotgun shell in a pocket of the pool table. Four other 12-gauge shotgun shells were found in a bowl, on top of which was Steiner’s notice of impending warrant of arrest. In addition to the shotgun ammunition, the police also discovered a variety of other types of ammunition, including 20 rounds of .32 caliber ammunition and 17 rounds of .38 Special ammunition.

Based on the shotgun and ammunition found in the camper, a grand jury charged Steiner with one count of being a felon-in-possession of a firearm and ammunition in violation of 18 U.S.C. § 922(g). A superseding indictment was filed several months later, adding a second count charging Steiner with a violation of § 922(g) based on the ammunition found in the home.

A. The Trial

1. Testimony

The government’s case against Steiner proceeded to a jury trial. At trial, Steiner stipulated to having a prior felony conviction. He testified in his own defense and denied that he ever owned or possessed the shotgun or ammunition seized from either the camper or the basement of the home. Steiner also acknowledged that he owned the wallet found in the camper and admitted that he owned the Meadow Avenue home at some point in 2007.

Steiner’s ex-wife, Greta Steiner, was called as a witness. She testified that although she had been living at a different address in 2007, she occasionally stopped at the Meadow Avenue home to retrieve her belongings. She also testified that during these visits she saw neither firearms nor ammunition in the home but she recalled having stored boxes of antique ammunition that belonged to her deceased ex-husband in the home’s garage. She denied that anyone ever brought the ammunition into the home and claimed that Steiner was unaware of the ammunition. Neither Steiner nor the government presented evidence about whether the ammunition stored in the garage may have been moved to the basement.

Mark Williams, Stants’ close friend, testified for the government. Williams claimed that he had been inside Steiner’s home in August 2007 because he was interested in purchasing the property. At that time, Williams said that he noticed the shotgun barrel and the hacksaw laying on a homemade bar and pointed them out to Stants. Williams also claimed that Steiner told him that he “wouldn’t go easy” if the police tried to arrest him.

Stants also testified. He denied receiving any benefit for his help in securing Steiner’s arrest, despite Baumgard’s testimony that he had paid Stants $100 for his assistance. He also corroborated Williams’ testimony regarding the basement of the home and admitted that he had visited Steiner’s home twice in Steiner’s absence.

2. The Government’s Arrest Warrant Evidence

During Steiner’s trial, the government introduced the arrest warrant that had issued based upon Steiner’s failure to appear on the sexual assault charge. The government argued that the arrest warrant, though not the underlying conduct, was admissible to show that Steiner “was on the run from law enforcement at the time, hiding out in this trailer,” and was intending to “evade the warrant and not appear” at the preliminary hearing because “[tjhat’s what led officers to his trailer in the first place.” The government claimed that the arrest warrant “completely] the story” because it was “background of what led law enforcement to Mr. Steiner to begin with in this case.” However, this was not true. Stants’ tip regarding the shotgun was the actual source of the government’s initial interest in Steiner. The District Court, relying on the government’s representation, admitted the arrest warrant evidence as “background” under Federal Rule of Evidence 404(b). The court reasoned that, as long as the underlying conduct was not admitted, any prejudice to Steiner was minimized. The court, though, expressly rejected any argument that the evidence could be admitted to prove Steiner’s motive or intent under Rule 404(b).

3. The District Court’s Juiy Instruction on Unanimity

The government requested that the jury be instructed that although the defendant was charged with possessing ammunition in different varieties or from different locations, it need not unanimously agree on which ammunition he possessed to convict him of felony possession under § 922(g). Steiner objected and requested that the jury be instructed that it must agree as to which ammunition Steiner possessed, adding the indictment was confusing. The District Court adopted the government’s position and instructed the jury that unanimity was not required with respect to the firearm or ammunition. Specifically, the court stated:

Although all jurors must agree with respect to Count 1 that the Defendant possessed a firearm or ammunition and with respect to Count 2 that the Defendant possessed different ammunition, you need not all agree on the exact item possessed. For example, if a Defendant was charged with possessing one piece of ammunition found in the bedroom, one piece of ammunition found in the living room, and one piece of ammunition found in the basement, you must all unanimously agree that the Defendant possessed at least one piece of ammunition in order to convict. You do not have to agree on which one or if he possessed more than one.
Therefore, it would be sufficient if ten jurors determined that he possessed one piece of ammunition in the bedroom, one juror determined that he possessed one piece of ammunition found in the basement, and one juror determined that he possessed them all. In other words, if the Defendant is alleged to have been in possession of ammunition of different varieties or from different locations, you must all find that as to the ammunition charged in each count he possessed at least some ammunition as charged in that count in order to convict, but ... need not all agree with respect to a count on exactly which ammunition was actually possessed as charged in that count.

The jury found Steiner not guilty on Count One (charging possession of the gun and ammunition in the camper), but guilty on Count Two (charging possession of the. ammunition found in the Meadow Avenue home).

II. Discussion

A. Admission of the Arrest Warrant

First, Steiner argues that the District Court erred by admitting evidence of the arrest warrant that had issued for his failure to appear at a preliminary hearing on an unrelated charge. The District Court stated during the in limine hearing on the admissibility of the arrest warrant, and memorialized in its minute entry, that its decision rested on Rule 404(b) grounds. Based on the government’s representations, the court admitted the evidence as “background” or to “complete the story” of the felon-in-possession crime.

Steiner argues that, while courts in this Circuit have occasionally admitted prior-act evidence under Rule 404(b) for the purpose of “completing the story” or providing “background,” they have also generally limited the use of those purposes to conspiracy cases. In response, the government asserts that the arrest warrant was properly admitted under Rule 404(b) because it identified a proper' purpose for the evidence: it was necessary to provide background and complete the story of Steiner’s arrest, interrogation, and the police investigation of the crimes charged.

For the reasons that follow, we conclude that the District Court erred by admitting the arrest warrant.

1. Admission of the Arrest Warrant Under Rule 404(b)

We review the District Court’s evidentiary rulings principally on an abuse of discretion standard, which occurs only when the district court’s decision is “arbitrary, fanciful, or clearly unreasonable”— in short, ■ where “no reasonable person would adopt the district court’s view.” We have “plenary review, however, of [the district court’s] rulings to the extent they are based on a legal interpretation of the Federal Rules of Evidence.” This includes plenary review “of whether evidence falls within the scope of Rule 404(b).”

Rule 404(b) provides that evidence of other crimes, wrongs, or acts is not admissible to prove character or dem-ónstrate action in conformity with those acts. Prior-act evidence, though, may be admitted “for another purpose, such as proving motive, opportunity,, intent, preparation, plan, knowledge, identity, absence of mistake, or lack of accident.” To be admissible, prior-act evidence must satisfy the test set forth in Huddleston v. United States. As the Supreme Court stated there, the proffered evidence must be: (1) offered for a proper purpose under Rule 404(b)(2); (2) relevant to that purpose; (3) sufficiently probative under the Rule 403 balancing requirement; and (4) accompanied by a limiting instruction, if requested. And, “unless the reason is apparent from the record, a mere list of the purposes found in Rule 404(b) is insufficient.” Indeed, “[t]he district court must put a chain of inferences into the record, none of which is the inference that the defendant has a propensity to commit this crime.”

In United States v. Green, we concluded that “allowing the jury to understand the circumstances surrounding the charged crime — completing the story — is a proper, non-propensity purpose under Rule 404(b).” We also stated that prior-act evidence is admissible to supply “helpful background information to the finder of fact.” With all of this in mind, one might ask: is not all evidence helpful to providing background to the factfinder? The answer is yes. But not all helpful evidence is relevant to a proper purpose under Rule 404(b).

In fact, Steiner is correct that the majority of criminal cases in which we have deemed “background” a proper purpose involve conspiracies. And there is no conspiracy involved in this case. Also, in at least one opinion that preceded' our decision in Green, we specifically warned that, while courts have occasionally admitted prior crimes evidence as “background,” “this label is uninformative at best and, at worst, can be an unacceptable substitute for the analysis required by Rule 404(b).”

There are unique characteristics that render “background” a proper purpose for admitting prior-act evidence in conspiracy eases. For instance, in proving the existence of a conspiracy, a court might allow a party to present background evidence revealing an ongoing relationship between co-conspirators. Likewise, this Court affirmed the admission of' background evidence to help the jury understand one conspirator’s role in a complex scheme. But neither of those models applies in this case.

Here, Steiner is the only defendant. There was no need for the government to explain a complicated back story. We are not suggesting that conspiracy cases are the only ones in which background facts may be admissible as 404(b) evidence. We are saying that, when the information needed to understand what happened in a case is straightforward and easily under-stood without reference to facts that do not bear on the charged offense, forcing extraneous and potentially prejudicial information into the record in the name of “background” is not defensible under Rule 404(b). That, unfortunately, is what happened here. Stants’ tip entirely explained why the government was focusing on Steiner. In fact, the arrest warrant evidence was completely irrelevant to the government’s case. We therefore find this case to be sufficiently distinct from cases in which “background” evidence may be admissible under Rule 404(b).

In Green, by contrast, we concluded that the background information — evidence that defendant threatened to kill a police officer — -was properly admitted under Rule 404(b) because it “fit into a logical chain of inferences” and explained why the defendant was under investigation for the crime charged, attempted possession with intent to distribute cocaine. We also held that the information was properly admitted for the purpose of proving the informant’s motive to cooperate, which was put at issue by the defendant. We therefore find Green distinguishable insofar as the prior-act evidence there served to complete the story of the crime charged. Here, we cpnclude that evidence of the outstanding arrest warrant on the unrelated sexual assault charge had nothing whatsoever to do with Steiner’s charged crime of felony possession of a weapon or ammunition under § 922(g).

Again, to be clear, we do not conclude that any evidence offered for the purpose of providing background is only admissible in conspiracy cases. There may — and likely will — be other situations in which such evidence is admissible outside of the conspiracy context. Nor do we venture to paint the absolute contours of when prior-act evidence may be admissible to provide background under Rule 404(b). We simply conclude that, on these facts, the District Court abused its discretion by admitting the arrest warrant evidence for the purpose of providing background.

To be sure, the District Court was not entirely, or even primarily, to blame for its error. The government played a central role. Here, the prosecutor wrongly asserted that the government needed the unrelated arrest warrant to prove that Steiner was guilty of felony possession. Yet it is clear to us that the government did not need the arrest warrant to try a case against Steiner at all. The government had Stants’ tip, Stants’ and Williams’ testimony that Steiner owned the home in 2007 and possessed a shotgun, and a stipulation that Steiner was a felon. Taken together, this evidence strongly supported the government’s theory that Steiner unlawfully possessed the firearm and ammunition. The only purpose the arrest warrant served was to improperly suggest that Steiner was predisposed to commit criminal acts.

In sum, we are deeply troubled by the government’s inaccurate claim that the arrest warrant was “what led officers to [Steiner’s] trailer in the first place,” and we are persuaded that that inaccuracy led the District Court to err by admitting evidence of the warrant. We therefore admonish the government to take greater care in its representations to the trial court and not brandish Rule 404(b) so cavalierly.

2. Whether the error was harmless

While we find that the District Court improperly admitted the arrest warrant, we conclude that the error was harmless. “[A]n error is harmless if it did not have a ‘substantial and injurious effect or influence in determining, the jury’s verdict.’ ” Moreover, we will uphold a conviction “if the reviewing court may confidently say, on the whole record, that the constitutional error was harmless beyond a reasonable doubt.”

First, the arrest warrant evidence had no prejudicial impact on the jury’s determination as to Count One, because Steiner was found not guilty of that charge. It is therefore reasonable to infer that the evidence had no effect as to Count Two. Second, the District Court did not disclose the conduct underlying the arrest warrant, that is, the alleged sexual assault of a minor. Third, at trial, Steiner stipulated to having a prior felony conviction. Also, when he took the stand, Steiner admitted that he was previously convicted of crimes of falsehood — burglary, theft, and felony forgery. And Anally, the ample evidence presented surrounding Steiner’s ownership and occupation of the home, Stants’ and Williams’ testimony regarding the same, and the lack of evidence linking the antique ammunition in the garage to the ammunition found in the home, convinces us that the additional arrest warrant evidence had no substantial or injurious effect on the jury’s guilty verdict as to Count Two.

We therefore conclude that any error in admitting the prior act evidence under Rule 404(b) was harmless.

B. Steiner’s Jury Instruction Challenge

Next, Steiner argues in his briefs that the District Court erred by refusing to instruct jurors that they must unanimously agree as to which ammunition he possessed to find him guilty under Count Two. In support of his claim, Steiner argues that the government improperly bundled into Count Two multiple, distinct violations of § 922(g), each of which should have been prosecuted as a separate violation of the statute. Put another way, he claims that the indictment was “duplicitous” because the government improperly joined possession of separate types of ammunition into one count. To cure this defect, Steiner contends that the District Court should have instructed the jury that it had to unanimously determine which ammunition Steiner possessed to find him guilty on Count Two. By expressly declining to give this curative jury instruction, Steiner argues that the District Court deprived him of his Sixth Amendment right to a unanimous jury verdict, and therefore his conviction under Count Two should be vacated.

We reject Steiner’s argument. In our view, the evidence at trial overwhelmingly demonstrated that Steiner possessed the ammunition in one part of the Meadow Avenue home, which he owned in 2007. For the additional reasons that follow, we therefore conclude the indictment properly charged Steiner with a single violation of § 922(g) under Count Two and that a special unanimity instruction was not required.

Whether an indictment is duplicitous is a question of law subject to de novo review. We also review de novo “whether the jury instructions stated the proper legal standard.” “We review the refusal to give a particular instruction or the wording of instructions for abuse of discretion.”

Duplicity is the improper combining of separate offenses into a single count. When a defendant’s Sixth Amendment right to a unanimous jury verdict is jeopardized by a duplicitous indictment, a court can cure the indictment by issuing a limiting instruction requiring the jury to unanimously find the defendant guilty of at least one distinct act.

Under Federal Rule of Criminal Procedure 12(b)(3)(B), a motion alleging a defect in the indictment must be made before trial. Yet while a defendant waives technical errors to an indictment by his failure to object to the duplicity before trial, courts have held that the alleged harm to the defendant’s substantive rights resulting from a duplicitous indictment can be raised at trial or on appeal, notwithstanding the defendant’s failure to make a pretrial motion. “The rationale for this distinction is that, whereas Rule 12 applies only to defects in the institution of criminal proceedings ... a verdict rendered by a less-than-unanimous jury violates a defendant’s Sixth Amendment rights by a harm that arises from the trial itself.”

Count Two of the indictment charged Steiner with a violation of 18 U.S.C. § 922(g), which, in relevant part, provides: “It shall be unlawful for any person who has been convicted in any court of a crime punishable by imprisonment for a term exceeding one year ... to ship or transport in interstate or foreign commerce, or possess in or affecting commerce, any firearm or ammunition; or to receive any firearm or ammunition which has been shipped or transported in interstate or foreign commerce.”

To determine whether Count Two was duplicitous, we first focus on the “allowable unit of prosecution” to decide whether the indictment properly charges a violation of the relevant statute. We have held that the allowable unit of prosecution under § 922(g) is the “incident of possession,” regardless of whether a defendant possessed more than one firearm, or possessed a firearm and ammunition. In other words, we ask if the evidence establishes that the defendant committed a single act of possessing firearms or ammunition, or instead whether the evidence indicates that multiple, distinct acts of unlawful possession occurred.

We have also stated that simultaneous possession of multiple firearms or pieces of ammunition does not give rise to a separate offense for each firearm or piece of ammunition possessed. Likewise, multiple convictions for possession of multiple firearms may be appropriate where the firearms in question were seized in different locations or if they were acquired in separate transactions.

These observations lead us to the question of how we determine whether an indictment is duplicitous when someone is charged with felony possession of various types of ammunition, all of which are located in the basement of a home. In resolving Steiner’s challenge, our prior cases provide us with sufficient guidance. In this case, we conclude that the indictment was not duplicitous and that a curative jury instruction was not required.

In United States v. Marino and United States v. Frankenberry, we held that the simultaneous possession or receipt of several firearms by a convicted felon constituted a single offense under the predecessor statutes to § 922(g), absent a showing that the weapons were separately stored or acquired. We further elaborated on the concept of simultaneous possession in United States v. Tann. In Tann, the indictment charged the defendant with two separate § 922(g) violations based upon possession of a gun found in the bathroom where he was arrested and ammunition that was located in his pocket at the same time. There, we determined that the two items were simultaneously possessed. As a result, we concluded that possession of both a firearm and ammunition, seized at the same time in the same location, supported only one conviction and sentence under § 922(g).

However, in United States v. Kennedy, we held that mere physical proximity does not demonstrate simultaneous possession. There, we declined to find simultaneous possession where firearms were stored in two separate vehicles located on the same premises. In reaching this conclusion, we specifically noted that, when determining whether firearms are simultaneously possessed, what matters is the defendant’s “course of ... treatment of the firearms,” which “may not be viewed in a frozen, momentary state immediately prior to the seizure.” We therefore held that the district court erred when it merged two separate felony possession counts for purposes of resentencing the defendant.

These cases demonstrate that determining whether individual firearms or ammunition were simultaneously possessed is a highly fact-driven inquiry that depends on the circumstances surrounding a defendant’s alleged conduct.

Here, other than Steiner’s testimony, there is little, if any, evidence supporting Steiner’s contention that the ammunition found in the home was acquired at different times and for different purposes, or that it was separately stored in the home. By contrast, the evidence at trial strongly demonstrated that Steiner owned the home in 2007 and that all of the ammunition was stored in various parts of the basement. Moreover, at least some of the 12-gauge ammunition was literally found resting under Steiner’s notice of impending warrant of arrest. And, while Steiner’s ex-wife testified that she brought various types of antique ammunition into the garage in 1999, none of the ammunition that Steiner was charged with possessing was located in the garage, and none of the physical evidence specifically linked the ammunition found in the basement to Greta Steiner or her deceased ex-husband. Moreover, even if we accepted that Greta Steiner purchased the ammunition found in the basement in the first instance, the jury could have found that Steiner himself later acquired the ammunition from Greta Steiner, and not, as Steiner claims, from other sources on other occasions.

In sum, we conclude that the indictment was not duplicitous. Accordingly, the District Court’s failure to give a special unanimity instruction as to Count Two did not constitute a violation of Steiner’s Sixth Amendment right to a unanimous jury verdict.

III. Conclusion

For the reasons set forth above, we will affirm the District Court’s judgment. 
      
      .This is an appeal from a judgment entered in the United States District Court for the Western District of Pennsylvania. Subject matter jurisdiction was conferred upon the District Court by 18 U.S.C. § 3231. We exercise appellate jurisdiction under 28 U.S.C. § 1291 and 18 U.S.C. § 3742(a).
     
      
      . The basement was also referred to in the indictment and at other points during trial as the “downstairs area.”
     
      
      . A forensic expert later matched the stock and barrel found in the basement to the sawed-off shotgun found in the camper.
     
      
      .The government proceeded against Steiner on a theory of constructive possession of the firearm in the camper and the ammunition found in his home. Constructive possession occurs when a person not in actual possession "knowingly has both the power and the intention at a given time to exercise dominion or control over a thing, either directly or through another person or persons.” United States v. Garth, 188 F.3d 99, 112 (3d Cir.1999) (internal quotation marks omitted).
     
      
      . Stants and Williams further testified that Steiner sold the house before police searched it, and Williams claimed that his wife had notarized the paperwork for that sale.
     
      
      . Our references to the unrelated arrest warrant are also, by extension, to any testimony or other evidence related to that warrant.
     
      
      . (App. at 116.)
     
      
      . (App. at 116.)
     
      
      . (App. at 487-88, 342.)
     
      
      . In its minute entry, the court stated: "[w]ith respect to the government's motion in limine on 404(b) evidence [Doc. No. 99], the government may, as background, refer to the fact that defendant was arrested on an outstanding warrant, but may not address the specifics of the warrant or underlying charge.” (App. at 28.) The District Court also stated numerous times on the record that the information was admitted only for background purposes. (App. at 117, 119.) Therefore, Steiner's argument that the District Court may have improperly admitted the arrest warrant evidence as "intrinsic” evidence that directly proved the crime, as opposed to prior-act evidence under Rule 404(b), is mer-itless.
     
      
      . United States v. Starnes, 583 F.3d 196, 214 (3d Cir.2009).
     
      
      . Complaint of Consolidation Coal Co., 123 F.3d 126, 131 (3d Cir.1997).
     
      
      . United States v. Cruz, 326 F.3d 392, 394 (3d Cir.2003).
     
      
      . Fed.R.Evid. 404(b)(1).
     
      
      . Fed.R.Evid. 404(b)(2)
     
      
      . 485 U.S. 681, 108 S.Ct. 1496, 99 L.Ed.2d 771 (1988).
     
      
      . Id. at 691-92, 108 S.Ct. 1496.
     
      
      . United States v. Sampson, 980 F.2d 883, 888 (3d Cir.1992).
     
      
      . Id.
      
     
      
      . 617 F.3d 233, 247 (3d Cir.2010).
     
      
      . Id. at 250.
     
      
      . See, e.g., United States v. O'Leary, 739 F.2d 135, 136 (3d Cir.1984) (identifying the need "to show the background of the charges [and] the parties' familiarity with one another” as a proper purpose); United States v. Simmons, 679 F.2d 1042, 1050 (3d Cir.1982) (admitting similar criminal activity perpetrated before the period charged in the indictment to furnish essential background information-, to demonstrate a continuing relationship between an unindicted co-conspirator and the defendant, and to assist the jurors in understanding the unindicted co-conspirator's role in the forgery scheme); United States v. Dansker, 537 F.2d 40, 58 (3d Cir.1976) (in conspiracy case, upholding introduction of prior criminal acts by defendants because "the background information provided by this testimony enabled the jury to better understand [the witness’s] role in the bribery scheme as well as his testimony as a whole”).
     
      
      . United States v. Echeverri, 854 F.2d 638, 644 (3d Cir.1988).
     
      
      . See, e.g., United States v. Corbin, No. 10-352, 2011 WL 2110831, at *2 (E.D.Pa. May 26, 2011) (finding that the defendants' prior gunpoint robberies of drug dealers were admissible to establish the relationships between the defendants and to explain the background of the conspiracy).
     
      
      . See United States v. Butch, 256 F.3d 171, 176 (3d Cir.2001) (finding no abuse of discretion and affirming conviction where the District Court admitted the government's background evidence "to help the jury understand the co-conspirator's role in the scheme”).
     
      
      . As to the second Huddleston factor, relevance, Fed.R.Evid. 401 provides that "[e]vi-dence is relevant if (1) it has any tendency to make a fact more or less probable than it would be without the evidence, and (2) the fact is of consequence in determining the action.”
     
      
      . Green, 617 F.3d at 250.
     
      
      . Id.
      
     
      
      . (App. at 116.)
     
      
      . Because we conclude that the District Court erred by admitting the arrest warrant evidence as "background,” we need not reach Steiner’s argument that the court failed to conduct a proper Rule 403 analysis. Nor need we reach the government’s argument that Steiner waived his Rule 403 argument by failing to object. And, as to the fourth Hud-dleston factor, we note that the District Court did not give a limiting instruction to the jury because Steiner did not request one.
     
      
      . Fed.R.Crim.P. 52(a) provides: "Any error, defect, irregularity, or variance that does not affect substantial rights must be disregarded.”
     
      
      . Bond v. Beard, 539 F.3d 256, 276 (3d Cir.2008) (quoting Brecht v. Abrahamson, 507 U.S. 619, 637, 113 S.Ct. 1710, 123 L.Ed.2d 353 (1993)).
     
      
      . Delaware v. Van Arsdall, 475 U.S. 673, 681, 106 S.Ct. 1431, 89 L.Ed.2d 674 (1986).
     
      
      . The government argues that Steiner waived any "duplicity” argument by not raising it below. We disagree. Steiner never moved to dismiss the indictment before or during trial on the grounds that the government improperly joined possession of separate types of ammunition into one count. However, Steiner’s counsel clearly objected to the jury instruction, specifically requesting that the jury be instructed that it must agree as to -which ammunition Steiner possessed and adding that the "indictment [c]ounts [were] confusing.” (App. at 97.) In consequence, we find that Steiner’s "duplicity” argument was preserved on appeal in connection with his jury instruction challenge.
     
      
      . Count Two of the indictment charged possession of various pieces of ammunition in the "downstairs area” of the home.
     
      
      . United States v. Haddy, 134 F.3d 542, 547 (3d Cir.1998).
     
      
      . United States v. Coyle, 63 F.3d 1239, 1245 (3d Cir.1995).
     
      
      . United States v. Leahy, 445 F.3d 634, 642 (3d Cir.2006).
     
      
      . United States v. Haddy, 134 F.3d 542 at 548.
     
      
      . See, e.g., United States v. Newell, 658 F.3d 1 (1st Cir.2011); United States v. Yielding, 657 F.3d 688 (8th Cir.2011); United States v. Pietrantonio, 637 F.3d 865 (8th Cir.2011); United States v. Starks, 472 F.3d 466 (7th Cir.2006).
     
      
      . United States v. Adesida, 129 F.3d 846, 849 (6th Cir.1997); see also United States v. Robinson, 627 F.3d 941, 958 (4th Cir.2010) (noting that ”[i]t is black letter law that duplicitous indictments can be cured through appropriate jury instructions.”); United States v. Haddy, 134 F.3d at 547-548.
     
      
      . United States v. Kakos, 483 F.3d 441, 444 (6th Cir.2007) (citing Davis v. United States, 411 U.S. 233, 241, 93 S.Ct. 1577, 36 L.Ed.2d 216 (1973)).
     
      
      . Haddy, 134 F.3d 542.
     
      
      . United States v. Tann, 577 F.3d 533, 537 (3d Cir.2009).
     
      
      . Id.
      
     
      
      . See, e.g., United States v. Verrecchia, 196 F.3d 294, 298 (1st Cir.1999) (concluding that the government properly charged the defendant with two counts of possessing a firearm in violation § 922(g) where twenty-three guns were recovered from the same defendant in two separate locations).
     
      
      . United States v. Marino, 682 F.2d 449, 454 (3d Cir.1982) (analyzing 18 U.S.C. § 1202(a)); United States v. Frankenberry, 696 F.2d 239, 245-46 (3d Cir.1982) (analyzing 18 U.S.C. § 922(h)).
     
      
      . Tann, 577 F.3d at 536-537.
     
      
      . Id. at 537.
     
      
      . 682 F.3d 244, 256 (3d Cir.2012).
     
      
      . Id.
      
     
      
      . Id. at 255-256.
     
      
      . Id.
      
     
      
      . While Stants and Mark Williams testified that Steiner sold the house before the August 29 search and that Williams’ wife notarized the paperwork, other testimony also confirms that Steiner owned the house sometime in 2007 before abandoning it.
     
      
      . Kakos, 483 F.3d at 446.
     
      
      . Steiner also asks us to reconsider our current legal standard for assessing claims of pre-indictment delay. See United States v. Beckett, 208 F.3d 140, 150-51 (3d Cir.2000) (defendant must show both actual prejudice and deliberate delay) (citing United States v. Ismaili, 828 F.2d 153, 168 (3d Cir.1987)). However, “[ujnder a longstanding practice of our Court, a panel may not overrule another panel decision.” Pa. Pharmacists Ass’n v. Houstoun, 283 F.3d 531, 534 (3d Cir.2002). We therefore will not undertake to reconsider our standard for reviewing claims of .pre-indictment delay. Moreover, we conclude that contrary to Steiner's assertion, the District Court applied the correct legal standard when it denied Steiner’s motion to dismiss the indictment for pre-indictment delay.
     