A "statement" for purposes of the hearsay prohibition against the admission of hearsay statements is (1) an oral or written assertion or (2) nonverbal conduct of a person, if it is intended by the person as an assertion.

Fed. R. Evid. 602 ("A witness may not testify to a matter unless evidence is introduced sufficient to support a finding that the witness has personal knowledge of the matter.").A person may testify to a matter only if there is sufficient evidence to show that the person has personal knowledge of the matter.

United States v. Valadez-Gallegos, 162 F.3d 1256, pin? (10th Cir. 1998) ("However, we may not uphold a conviction obtained by piling inference upon inference. United States v. Jones, 44 F.3d 860, 865 (10th Cir. 1995). 'An inference is reasonable only if the conclusion flows...Although proof of criminal guilt can rest on chains of inferences, such pyramided inferences must be reasonable.

United States v. Naylor, 705 F.2d 110, 111-112 (4th Cir. 1983) (upholding trial court's admission into evidence of accused's 1980 conviction for attempted theft of a motor vehicle where it constituted a prior similar act which proved his knowledge that the vehicle was stolen, as an essential element of...Evidence of a criminal or wrongful act apart from the act that at issue at trial Is not barred by the prohibition against circumstantial use of character if intent, knowledge, mistake, or accident is a legally-material factual issue, the opposing party suggests the non-existence of knowledge or urges mistake or accident as a defense, and evidence of another crime, wrong, or act is offered to prove the knowledge or the absence of mistake or accident by a criminal defendant or other person.