A person's other crimes, wrongs, or acts are not barred by the character rule either if they are not offered to show that person's propensity or if they are not offered to show that that person engaged in conduct on a particular occasion because of his or her propensity to engage in that sort of conduct.

United States v. Saadey, 393 F.3d 669, 679-680 (6th Cir. 2005) (upholding trial court's admission into evidence of the credit applications because they were adequately authenticated as "the government presented known....A person's handwriting may be authenticated by a lay witness -- i.e., a lay witness may identify the author of handwriting -- if the witness is personally familiar with the putative author's handwriting and the witness did not acquire such familiarity for purposes of the litigation.

United States v. Hall, 419 F.3d 980, 987 (9th Cir. 2005) (holding that the trial court properly admitted the hearsay statements of defendant's girlfriend because they were introduced in a supervised release....The Due Process and Compulsory Process guarantees give a defendant in a federal or state criminal trial the constitutional right, not only to compel the attendance of defense witnesses, but also to introduce trustworthy hearsay evidence that is critical or important to the defendant's defense.

Cf. United States v. Gonzales, 436 F.3d 560, 578-579 (5th Cir. 2006) (holding that the defendants' "compulsory process rights were not plainly violated by the government's failure to produce deported witnesses," considering that....The prohibition, grounded in the Compulsory Process Clause, against deliberate government action that deprives a criminal defendant of the relevant and material exculpatory testimony of a witness may effectively limit the government's use of hearsay evidence against a criminal defendant.