
    Idajete BOJKU, Riza Bojku, Marsel Bojku, Julian Bojku, Petitioners, v. Eric H. HOLDER, Jr., United States Attorney General, Respondent.
    No. 09-4378-ag.
    United States Court of Appeals, Second Circuit.
    July 7, 2010.
    Andrew P. Johnson, New York, NY, for petitioners.
    Tony West, Assistant Attorney General; Lyle D. Jentzer, Senior Litigation Counsel; Aaron R. Petty, Office of Immigration Litigation, United States Department of Justice, Washington, D.C., for respondent.
    PRESENT: JON O. NEWMAN, JOSÉ A. CABRANES, DEBRA ANN LIVINGSTON, and Circuit Judges.
   SUMMARY ORDER

Petitioners, natives and citizens of Albania, seek review of a September 22, 2009 order of the BIA, affirming the March 25, 2005 decision of Immigration Judge (“IJ”) Helen Sichel, which denied their application for asylum and withholding of removal. In re Bojku, Nos. [ AXXX XXX XXX ]/867/868/869 (B.I.A. Sept. 22, 2009), aff'g Nos. [ AXXX XXX XXX ]/867/868/869 (Immig. Ct. N.Y. City Mar. 25, 2005). We assume the parties’ familiarity with the underlying facts and procedural history in this case.

Under the circumstances of this case, we review the decision of the IJ as supplemented by the BIA. See Yan Chen v. Gonzales, 417 F.3d 268, 271 (2d Cir.2005). The applicable standards of review are well-established. See Bah v. Mukasey, 529 F.3d 99, 110 (2d Cir.2008); Shu Wen Sun v. BIA, 510 F.3d 377, 379 (2d Cir.2007).

Substantial evidence supports the agency’s adverse credibility determination. In finding Riza Bojku’s testimony not credible, the IJ relied in large part on his demeanor, specifying at least four instances where he paused before answering when asked to describe the persecution he allegedly suffered, and finding that “throughout much of the testimony [he] was straggling to remember the answers to questions as though he was attempting to remember the lines in a perfectly memorized script.” IJ at 8. Because the IJ was in the best position to observe Bojku’s manner while testifying, we afford her demeanor finding particular deference. See Li Hua Lin v. U.S. Dep’t of Justice, 453 F.3d 99, 109 (2d Cir.2006); Zhou Yun Zhang v. INS, 386 F.3d 66, 73-74 (2d Cir.2004), overruled on other grounds by Shi Liang Lin v. U.S. Dep’t of Justice, 494 F.3d 296 (2d Cir.2007) (en banc).

Having found Bojku’s testimony not credible, the agency reasonably found that his documentary evidence was questionable, Biao Yang v. Gonzales, 496 F.3d 268, 273 (2d Cir.2007), and did not err in rejecting Petitioners’ purported government-issued documents in part because they were not authenticated in compliance with 8 C.F.R. § 287.6, see Shunfu Li v. Mukasey, 529 F.3d 141, 149 (2d Cir.2008); Qin Wen Zheng v. Gonzales, 500 F.3d 143, 148 (2d Cir.2007) (distinguishing Cao He Lin v. U.S. Dep’t of Justice, 428 F.3d 391, 404-05 (2d Cir.2005), and holding that the BIA did not err in rejecting a document in part due to lack of authentication); Matter of H-L-H-, 25 I. & N. Dec. 209, 214 & n. 5 (BIA 2010) (reasoning that authentication is more reasonably expected when the applicant’s family allegedly sought out evidence from authorities on the applicant’s behalf for the purpose of asylum proceedings, as opposed to a contemporaneously created report of a past event). Furthermore, the certificate allegedly issued by the Albanian Democratic Party did not confirm Bojku’s claim that he was arrested and mistreated due to his political opinion. When asked why the certificate did not mention his alleged arrest and mistreatment, Bojku was unable to explain the omission. Contrary to Petitioners’ argument that the agency did not identify any “inconsistency” between Bojku’s testimony and his written statement, the omission the IJ identified was the functional equivalent of an inconsistency and supported the IJ’s adverse credibility determination. See Xiu Xia Lin v. Mukasey, 534 F.3d 162, 166 n. 3 (2d Cir.2008).

Ultimately, because a reasonable fact-finder would not be compelled to conclude to the contrary, the IJ’s adverse credibility determination was supported by substantial evidence. See Shu Wen Sun, 510 F.3d at 379-80; see also Xian Tuan Ye v. Dep’t of Homeland Security, 446 F.3d 289, 294 (2d Cir.2006). Accordingly, the agency did not err in denying Petitioners’ applications for asylum and withholding of removal. See Paul v. Gonzales, 444 F.3d 148, 156 (2d Cir.2006).

Finally, the agency did not err in failing to address the possibility of CAT relief, because Petitioners expressly waived this form of relief before IJ, and only mentioned it glancingly in their brief before BIA. See Lin Zhong v. U.S. Dep’t of Justice, 480 F.3d 104, 122 (2d Cir.2007); see also Yueqing Zhang v. Gonzales, 426 F.3d 540, 545 n. 7 (2d Cir.2005) (noting that an argument is not considered raised when it is mentioned in a “single conclusory sentence”).

For the foregoing reasons, the petition for review is DENIED. As we have completed our review, any stay of removal that the Court previously granted in this petition is VACATED, and any pending motion for a stay of removal in this petition is DISMISSED as moot. Any pending request for oral argument in this petition is DENIED in accordance with Federal Rule of Appellate Procedure 34(a)(2), and Second Circuit Local Rule 34.1(b). 
      
      . While Idajete Bojku was designated the lead applicant, Petitioners’ claims were predicated solely on the alleged persecution of her husband, Riza Bojku. For the sake of clarity, we refer to him as "Bojku” throughout.
     
      
      . We decline to address Petitioners' arguments relating to the parties' stipulation because they failed to exhaust this issue before the BIA. See Lin Zhong v. U.S. Dep’t of Justice, 480 F.3d 104, 121-22 (2d Cir.2007).
     