See note 14, supra. In Commonwealth v. MacDonald, 459 Mass. 148, 156, 945 N.E.2d 260 (2011), this court discussed an expert's visual (and tactile) identification of marijuana. At trial, the expert examined the substance through a clear plastic bag and stated that the seeds were “consistent with” marijuana.
2. Discussion. “In a case involving a narcotics offense, the Commonwealth must prove beyond a reasonable doubt that the substance at issue ‘ “is a particular drug” because such proof is an element of the crime charged.’ ” Commonwealth v. MacDonald, 459 Mass. 148, 153, 945 N.E.2d 260 (2011), quoting from Commonwealth v. Vasquez, 456 Mass. 350, 361, 923 N.E.2d 524 (2010). The Commonwealth cannot meet
Proof of a drug's identity “may be made by circumstantial evidence, including the testimony of experienced police officers. An individual's familiarity with the properties of marijuana through past experience coupled with present observation of the substance at issue is sufficient to establish its identity.” Commonwealth v. MacDonald, 459 Mass. 148, 153 (2011) (citations omitted). The first witness's testimony regarding the identity of the substance drew no objection.
In arguing the trooper's statements were insufficient, the probationer cites cases concerning criminal prosecutions where the statements at issue were scrutinized under the “beyond a reasonable doubt” standard of proof. See, e.g., Commonwealth v. MacDonald, 459 Mass. 148, 154 (2011), quoting Commonwealth v. Dawson, 399 Mass. 465, 467 (1987) (“it would be a rare case in which a witness's statement that a particular substance looked like a controlled substance would alone be sufficient to support a conviction”). They are thus inapposite here, where the judge “need find only by a preponderance of the evidence that a violation has occurred.”
Instead, the Commonwealth could have proven its case, as case law permits, using only circumstantial evidence of the identity of the substances suspected to be narcotics. See Commonwealth v. MacDonald, 459 Mass. 148, 154 (2011); Commonwealth v. Dawson, 399 Mass. 465, 467 (1987).
" Commonwealth v. Tanner, 45 Mass. App. Ct. 576, 579 (1998) (citation omitted). See Commonwealth v. MacDonald, 459 Mass. 148, 163 (2011). For example, in Woods, the court found that, although the question was a "close one," percipient police officers' "testimony that the defendant was involved in a drug sale was, in effect, expert opinion that the defendant was guilty of the charges" and that "[s]uch expert opinion testimony was unnecessary and impermissibly intruded on the jury's vital fact finding function."
Similar to the evidence of the witness's recantation in Ferrara, the evidence regarding Ms. Dookhan's misconduct is " ‘ of enormous significance for impeachment purposes[, ]’ " see id., and may preclude a jury from finding that the Commonwealth has met its burden beyond a reasonable doubt. See, e.g., Commonwealth v. MacDonald, 459 Mass. 148, 153 (2011) (" In a case involving a narcotics offense, the Commonwealth must prove beyond a reasonable doubt that the substance at issue " ‘ is a particular drug" because such proof is an element of the crime charged.’ " (citation omitted)); cf. Commonwealth v. Bly, 448 Mass. 473, 485 (2007) (defining " exculpatory evidence" as favorable evidence " that is of significant aid to [the defendant's] case, ‘ whether it furnishes corroboration of the defendant's story, calls into question a material, although not indispensable, element of the prosecution's version of the events, or challenges the credibility of a key prosecution witness ’ " (emphases added)).
As the BIA found, Mass. Gen. Laws ch. 94C § 32 is divisible because Massachusetts case law is clear: the specific controlled substance charged is an element of the offense. See Commonwealth v. MacDonald, 945 N.E.2d 260, 265 (Mass. 2011) (explaining that the prosecution must "prove beyond a reasonable doubt that the substance at issue is a particular drug because such proof is an element of the crime charged" (emphasis added) (internal quotation marks omitted)); Commonwealth v. Vasquez, 923 N.E.2d 524, 534 (Mass. 2010) (same).
See G. L. c. 94C, § 32A (a ) ("Any person who knowingly or intentionally manufactures, distributes, dispenses or possesses with intent to manufacture, distribute or dispense a controlled substance ... shall be punished ..."). That, in rare instances, proof that a suspected illegal substance sold by a defendant was an illegal drug can be established in other ways, such as the testimony and observation of an experienced user of the drug, see Commonwealth v. MacDonald, 459 Mass. 148, 153-154, 945 N.E.2d 260 (2011), does not change this calculus.
The "risk of prejudice is great where a percipient witness comments on a defendant's guilt because the line between ‘specific observations and expert generalizations [becomes] blurred,’ " and "[i]t may result in improper vouching by the Commonwealth." Commonwealth v. MacDonald, 459 Mass. 148, 163, 945 N.E.2d 260 (2011), quoting Commonwealth v. Tanner, 45 Mass. App. Ct. 576, 579, 700 N.E.2d 282 (1998). In determining whether an expert witness's testimony was permissible, "the better practice is to focus the analysis on whether the evidence is explanatory," as opposed to "conclusory" or "couched simply in terms of whether a defendant did or did not commit a particular offense" (emphasis in original).