A specific act of a witness sometimes may be used to impeach a witness, but if the act to be used for impeachment is similar to an act at issue in the trial, the risk of undue prejudice may increase and the trial court may therefore have more reason to exclude the impeaching act as unduly prejudicial.

Combs v. Wilkinson, 315 F.3d 548, 554-556 (6th Cir. 2002) (holding, in plaintiff death row inmates' civil rights action against defedant corrections supervisors and officers for use of excessive force, that the trial....An exception to the hearsay rule applies to the following records of government offices and agencies: (A) public records that set forth the activities of the government office or agency; (B) public records that set forth observations that a government office or agency was required to make and report but this exception does not apply in criminal cases to observations of police officers and other law enforcement personnel; or (C) in civil actions and proceedings and in criminal cases when offered against the government, factual findings resulting from an investigation made pursuant to authority granted by law, unless the sources of information or other circumstances indicate the untrustworthiness of such findings.

United States v. Malpica-Garcia, 489 F.3d 393, 396 (1st Cir. 2007) (upholding trial court's admission of testimony given by government witness which did not violate defendant's rights under the Confrontation Clause because....The Sixth Amendment Confrontation Clause places no limits on the admission at trial of nonhearsay statements made prior to or outside of trial.

Rowland v. American General Finance, Inc., 340 F.3d 187, 195 (4th Cir. 2003) (holding, in plaintiff administrative assistant manager's sexual discrimination action against defendant employer, that defendant's argument that the letter....The catchall or omnibus hearsay exception created by Federal Rule of Evidence 807 or a comparable State rule is available only if the proponent of a statement under this exception makes known to the adverse party sufficiently in advance of the trial or hearing to provide the adverse party with a fair opportunity to prepare to meet the statement, the proponent's intention to offer the statement and the particulars of it, including the name and address of the declarant.