Admitting Expert's Opinion Testimony On The Expert's Possible Experimental Waste And Error

In possession with intent to distribute five grams or more of cocaine base prosecution, admitting under FRE 702 expert forensic chemist testimony concerning the quantity of the seized substance based upon expert's estimate of the amount of crack cocaine consumed during testing to explain why the laboratory weight was less than the charged weight of five grams, in United States v. Finch, _ F.3d _ (8th Cir. Jan. 6, 2011) (No. 10-1157)

Often in performing tests to identify prohibited substances, an amount of the substance must be consumed to successfully complete the identification. As a result, where a defendant is tried for possesssion of an illegal substance, often part of that substance must be destroyed in testing to identify it. Can the government bolster its case by having its expert assess and explain how experimental error and the necessity to destroy a portion of the substance suggested that the defendant had in his possession a certain amount of weight? The Eighth Circuit recently explained why the expert will be able to vouch for him or herself.

In the case, defendant Finch was charged with possession with intent to distribute 5 grams or more of cocaine base. This was based upon discovery in his room of drug paraphernalia, including "105 small[] green plastic bags, each containing a white rock-like substance that the officer suspected to be illegal drugs. Tests later confirmed that the substance was crack cocaine." Fitch __ F.3d at __. One issue of focus at trial was whether the defendant actually possessed over 5 grams of crack in the 105 small plastic bags that were discovered. This became an issue because the expert's "final weighing [of the alleged crack] resulted in a weight of less than 5 grams" yet the defendant was charged with having more than that amount. To support its argument that the defendant had possessed at least 5 grams, the prosecutor elicited testimony from the expert explaining that "0.76 grams plus a theoretical minimum weight of 4.25 grams would yield an original amount of more than 5 grams," supporting a jury finding as to the charged amount of contraband. Fitch __ F.3d at __

The jury convicted the defendant and he appealed, contending that the expert testimony estimating the amount of crack destroyed in identifying the crack was an erroneously admitted. The Eighth Circuit rejected this argument and affirmed the admission of the expert testimony, including the expert's estimate on the amount of crack the defendant had in his possession.

According to the Circuit, such expert testimony had merit and should be admitted:

Finch argues that [expert] Cowan's estimate that the testing process consumed at least 0.76 grams of crack cocaine was 'mere conjecture.' We disagree. Cowan initially testified that, in the course of her career, she had tested thousands of samples of substances, including several hundred samples of crack cocaine. Additionally, she later confirmed that her experience in analyzing and weighing small quantities of powdery substances gave her 'a better judgment about the quantities involved ... than a layperson.' Cowan then testified that the contents of each of the 105 bags weighed between 0.04 grams and 0.11 grams. Based on her experience in weighing these small quantities of powdery substances and extracting portions of them for testing, Cowan explained that it was common to consume one quarter of “a small sample like the 0.04 [sample].” Because one quarter of 0.04 grams-the smallest sample-is 0.01 grams, Cowan could estimate that, at a bare minimum, she had consumed 1.05 grams of crack cocaine during testing (0.01 grams multiplied by 105 bags), well in excess of the 0.76-gram 'threshold.' We conclude that Cowan's expert testimony was not 'fundamentally unsupported' and that its admission did not constitute an abuse of discretion.
Fitch __ F.3d at __ (citing United States v. Rodriguez, 581 F.3d 775, 795 (8th Cir. 2009) (“The factual basis of an expert opinion goes to the credibility of the testimony, not the admissibility, and it is up to the opposing party to examine the factual basis for the opinion in cross-examination.”; “Only if an expert’s opinion is so fundamentally unsupported that it can offer no assistance to the jury must such testimony be excluded.”) (other citation omitted), cert. denied, 562 U.S. _ (U.S. Oct. 18, 2010))

Federal Rules of Evidence
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