Guide to Evidence  Significant Updates to the 2024 Edition

Illustrations.

- Prior Interactions with Police.

Evidence that a police officer is familiar with the defendant from previous interactions should be treated with caution because it may suggest that the defendant engaged in prior bad acts and might be taken by the jury as impermissible evidence of criminal propensity. Commonwealth v. Cintron, 103 Mass. App. Ct. 799, 804 (2024). When previous interactions with the police implicate a prior bad act, such evidence should generally be avoided. Id. Evidence of an officer's knowledge of the defendant from past dealings is admissible, however, if relevant for a nonpropensity purpose and not outweighed by the risk of unfair prejudice to the defendant. See Commonwealth v. Henley, 488 Mass. 95, 126 (2021) (fact and duration of police officer's familiarity with defendant relevant to strength of identification); Commonwealth v. Westbrook, 58 Mass. App. Ct. 692, 699 (2003) (evidence that police officer had dealings with defendant one week prior to crime relevant to explain how the police officers knew where the defendant lived and did not necessarily imply prior involvement in criminal activity). Where the police officer’s contact with the defendant arose in a non-work setting, the better practice is to avoid reference to the officer’s employment. See Commonwealth v. Pleas, 49 Mass. App. Ct. 321, 328−329 (2000) (police officer's familiarity with defendant from social interactions relevant to establish foundation for officer to identify defendant in videotape of crime and not unduly prejudicial where no evidence was admitted to suggest officer knew defendant from "prior adversarial encounters with law enforcement authorities").

- Statements About Other Acts.

See Commonwealth v. Lora, 494 Mass. 235, 246 (2024) (social media posts by defendant three weeks after shooting, including, "[G]od protect me from my friends[.] [I] can take care of my enemies," properly admitted to show defendant’s state of mind, retaliatory intent, and to rebut his claim of self-defense).

- Certitude of Expert Witness Opinion.

Testimony that a latent fingerprint matches a known print (using ACE-V method) should be presented as an opinion and not a fact, and opinions expressing absolute certainty of a print are to be avoided. Commonwealth v. Escobar, 493 Mass. 694, 714 (2024); Commonwealth v. Honsch, 493 Mass. 436, 452–454 (2024).

Illustrations.

- Fingerprints. See Commonwealth v. Patterson, 445 Mass. 626, 641–655 (2005). See also Commonwealth v. Joyner, 467 Mass. 176, 177 (2014) (testimony of fingerprint expert did not violate prohibition against expressing an opinion to a scientific certainty that there was a match). Where a fingerprint is the only identification evidence, the Commonwealth must prove beyond a reasonable doubt that the fingerprint was placed during the commission of the charged crime. Commonwealth v. French, 476 Mass. 1023, 1024–1025 (2017). Unlike DNA evidence, the statistical significance of an opinion about a match is not a foundational requirement but may affect the weight of the evidence. Commonwealth v. Wadlington, 467 Mass. 192 (2014). Cf. Commonwealth v. Gambora, 457 Mass. 715, 724–725 (2010) (considering report by National Research Council, Strengthening Forensic Science in the United States: A Path Forward 102–104, 136–145 [2009]). A fingerprint expert may not express an "absolute certainty" that a match exists. Commonwealth v. Escobar, 493 Mass. 694, 714–715 (2024). It is not enough for an expert to avoid testifying that the match is 100 percent certain; the Commonwealth has an affirmative duty to elicit on direct examination the expert’s testimony that the match is an opinion based on the expert's education, training, and experience. Commonwealth v. Robertson, 489 Mass. 226, 238 (2022) (prosecutor must ask whether witness has an opinion "to a reasonable degree of fingerprint analysis certainty"). No evidentiary hearing is needed, and a judge may take judicial notice, where expert testifies to a method of fingerprint analysis that has previously been found to be reliable. Commonwealth v. Honsch, 493 Mass. 436, 450 (2024) (ACE-V method of fingerprinting).