Cir.2009), because the admission of the various evidence in question was not contested below, we review these claims only for plain error, see United States v. Garcia, 413 F.3d 201, 219 (2d Cir.2005). Under this standard, relief is available only where there is an “(1) error, (2) that is plain, and (3) affects substantial rights, and (4) the error ‘seriously affects the fairness, integrity, or public reputation of judicial proceedings.’ ” Bell, 584 F.3d at 484 (quoting United States v. Weintraub, 273 F.3d 139, 145 (2d Cir.2001)). Li’s claims of forgery and tampering are unsupported and conclusory and mainly constitute a challenge to the credibility of the witnesses. Such allegations are insufficient to form a basis for reversal. See United States v. Moore, 54 F.3d 92, 99 (2d Cir.1995) (<HOLDING>). Finally, with the exception of Li’s claim of
holding that a defendants false grand jury testimony was insufficient to establish perjury where the defendant was called before the grand jury for the mere purpose of laying the foundation for a perjury prosecution such testimony was immaterial to the grand jurys purpose holding that a conviction violated due process because the prosecutor knowingly allowed a government witness to commit perjury holding that allegations of perjury require a demonstration that the witnesses actually committed perjury holding that fact that one witnesss testimony is at odds with testimony of another witness does not supply a sufficient basis for allegations of perjury holding that the perjury by a key government witness irrespective of whether the government knew of the perjury at the time of trial infected the trial proceedings and required reversal