Is there any case law where a federal court has found that the testimony of a former federal detective, who testified that a person carrying contraband was not a suspect in the case, inherently improbable?

The federal court apparently found detective Mauerhan's testimony inherently improbable, and we agree the testimony contains matters quite contrary to the way one would expect a person carrying contraband to behave. However, testimony which discloses unusual circumstances is not for that reason alone inherently improbable. (People v. Barnes, supra, 42 Cal.3d at p. 306, 228 Cal.Rptr. 228, 721 P.2d 110.) Likewise, the circumstance that there is testimony that a person suspected of crime did some particular act directly contrary to his or her interests does not necessarily compel the conclusion the suspect did not, in fact, do such act. (People v. James, supra, 19 Cal.3d at pp. 113-114, 137 Cal.Rptr. 447, 561 P.2d 1135.)