tion precedent to admissibility is satisfied by evidence sufficient to support a finding that the matter in question is what its proponent claims.” The rationale is that in the absence of showing that the evidence is what its proponent alleges, the evidence is simply irrelevant. E. Morgan, Basic Problems of State and Federal Evidence, 327 (5th ed.1976); see also, 7 J. Wigmore, Wig-more on Evidence § 2129 at 703 (Chad-bourn rev.1978) (authenticity is an “inherent logical necessity”).
The condition precedent to the admission of real evidence is met by providing the proper foundation. If the proffered evidence is unique, readily identifiable and relatively resistant to change, the foundation need only consist of testimony that the evidence is what its proponent claims. E. Cleary, McCormick on Evidence § 212 at 667 (3d ed.1984). However, when the evidence, as here, is not readily identifiable and is susceptible to alteration by tampering or contamination, the trial court requires a more stringent foundation “entailing a ‘chain of custody’ of the item with
sufficient completeness to render it
improbable that the original item has either been exchanged with another or been contaminated or tampered with.” (Emphasis added.)
Id. at 668;
accord United States v. Luna, 585 F.2d 1, 6 (1st Cir.),
cert. denied,
439 U.S. 852, 99 S.Ct. 160, 58 L.Ed.2d 157 (1978);
Gallego v. United States, 276 F.2d 914, 917 (9th Cir.1960).
This circuit’s controlling test for the admission and exclusion of real evidence under Fed.R.Evid. Rule 901(a) was clearly enunciated in Reed v. United States, 377 F.2d 891, 893 (10th Cir.1967) (citing Brewer v. United States, 353 F.2d 260 (8th Cir.1965)). Before admitting or excluding real evidence, the trial court must consider the nature of the evidence, and the surrounding circumstances, including presentation, custody and probability of tampering or alteration. If, after considering these factors, the trial court determines that the evidence is substantially in the same condition as when the crime was committed, the court may admit it. Reed, 377 F.2d at 893.
The cocaine, not uniquely identifiable, requires a sufficient chain of custody to support its admission. However, the chain of custody need not be perfect for the evidence to be admissible. United States v. Mora, 845 F.2d 233, 236-37 (10th Cir.). cert. denied, — U.S. -, 109 S.Ct. 562, 102 L.Ed.2d 587 (1988); United States v. Lepanto, 817 F.2d 1463, 1466-67 (10th Cir.1987). The well-established rule in this circuit is that deficiencies in the chain of custody go to the weight of the evidence, not its admissibility; once admitted, the jury evaluates the defects and, based on its evaluation, may accept or disregard the evidence. United States v. Brandon, 847 F.2d 625, 630 (10th Cir.) cert. denied, — U.S. -, 109 S.Ct. 510, 102 L.Ed.2d 545 (1988); Mora, 845 F.2d at 237 (citing United States v. Gay, 774 F.2d 368 (10th Cir.1985)); United States v. Drumright, 534 F.2d 1383, 1385 (10th Cir.), cert. denied, 429 U.S. 960, 97 S.Ct. 385, 50 L.Ed.2d 327 (1976).
On appeal, defendant alleges that there was an insufficient chain of custody to support the trial court’s admission of the cocaine since Officer Gunter, who had custody of it from the time of its initial seizure until he delivered it to the evidence room, was unavailable to testify. Based on this, defendant contends that the cocaine should not have been admitted since there was a “substantial break in the chain.”
From the moment Officer Garcia seized the cocaine from Cardenas’ truck, its whereabouts were accounted for. Testimony at trial by Officers Garcia and Mares shows that there was no substantial break in the chain. Upon seizing the cocaine, Officer Garcia handed it to Officer Gunter who, in turn, displayed it to Officer Mares. Admittedly Officer Mares could not absolutely identify the plastic sack containing white powder offered at trial as that seized from the truck. However, given that the plastic sack was not uniquely identifiable and considering his testimony that the evidence at trial in every respect resembled the evidence seized from the truck, the lack of absolute identification does not amount to an insufficient chain of custody. See