In United States v. Weiner, 479 F.2d 923 (2d Cir. 1973), the appellant was convicted based on the direct testimony of the principal witness who stated that he had multiple telephone conversations with the appellant (a claim the appellant denied), along with phone company records and testimony from a second witness about a telephone call between the second witness and the appellant followed by a call from the principal witness to the second witness. Id. at 924-25, 929.
In determining that this evidence was sufficient to satisfy the two-witness rule, the Court noted that the requirement of a second witness may be fulfilled by "other evidence of independent probative value, circumstantial or direct, which is of a quality to assure that a guilty verdict is solidly founded." Id. at 926, 928-29.