[N]ot infrequently the commission of a criminal offense is followed immediately by an active attempt to conceal it. Thus, a rule has arisen to the effect that the declarations of a co[-]conspirator are admissible against a co[-]conspirator not only when they are made during the perpetration of the offense, but also when expressed during the course of a subsequent attempt to conceal the crime and relating to it.
Id., slip op. at 26 (quoting United States v. Taylor, 6 C.M.A. 289, 293, 20 C.M.R. 5, 9 (!955) (second and third alterations in the original)).