Extrinsic evidence may be used to to impeach a witness by showing the bias or interest of the witness; i.e., the party seeking to impeach a witness by showing bias or interest is not limited to the testimony of the target witness and may use evidence other than the testimony of the target witness to show the bias or interest of the target witness.

United States v. Adefehinti, 510 F.3d 319, 326-327 (D.C. Cir. 2007) (upholding trial court's admission of loan documents [which were based on certificates provided by the records' custodians] as business records exception....There is a hearsay exception for a memorandum, report, record, or data compilation, in any form, of acts, events, conditions, opinions, or diagnoses, made at or near the time by, or from information transmitted by, a person with knowledge, if kept in the course of a regularly conducted activity of a business, institution, association, profession, occupation, or calling if it was the regular practice of that business, institution, association, profession, occupation, or calling to make the memorandum, report, record or data compilation, unless the source of information or the method or circumstances of preparation indicate lack of trustworthiness.

Radiant Burners, Inc. v. American Gas Association, 320 F.2d 314, 318 (7th Cir. 1963) ("With deference to the ingenuity and judicial courage" of the trial judge who ruled that corporations do not have the benefit of the attorney-client privilege, the court of appeals holds that the privilege extends to...Private corporations and other private organizations and associations can hold the attorney-client privilege.

United States v. Rakes, 136 F.3d 1, 3 (1st Cir. 1998) ("that the Rakeses [husband and wife] later divorced is irrelevant" to the protection offered by the privilege).If a communication between husband and wife was made during the marriage and is protected by the confidential marital communications privilege, termination of the marriage by death or divorce does not extinguish the protection of the privilege for such communications made during the marriage.