In Commonwealth v. Akara, the Massachusetts Supreme Judicial Court considered whether evidence of a defendant's "gang affiliation" was properly admissible in his murder trial on a theory of joint venture.
In that case, the defendant was charged as a joint venturer in the murder of Philip Gadsden at an MBTA station.
At trial, the government introduced evidence of the defendant's gang affiliation through the testimony of a Boston Police Officer. The officer testified that the Boston Police Department classifies any group or association of four or more people who call themselves by a group name and have various identifying signs, symbols or clothing. At trial, witnesses testified that the defendants were associated with a particular gang, but there was no evidence of any specific criminal activity by this gang other than alleged vandalism.
Notably, there was also no evidence of any motive for the murder or that the victim was associated with any "rival" gang.
Gang evidence may be admissible in criminal trials to show motive or to establish "joint venture". Although the gang evidence in this case did not go to establish motive, the Massachusetts Supreme Court held that it was properly admitted to establish evidence of the defendants' relationship, which in turn bolstered the prosecutor's theory of joint venture.
This is not to say that all evidence of gang affiliation is automatically admissible in criminal trials. Defense attorneys will make efforts to exclude gang evidence at trial, particularly where a defendant's purported gang membership is so prejudicial that it might suggest to a jury that he has a propensity to crime of violence.