According to Massachusetts’ “joint venture” theory, a defendant may be charged with a crime if he aided or abetted the person who committed the criminal act.
The Supreme Judicial Court has held that a joint venture exists when the defendant was
(1) present at the scene of the crime,
(2) with knowledge that another intends to commit the crime or with intent to commit a crime, and
(3) by agreement is willing and available to help the other if necessary.Commonwealth v. Cohen, 412 Mass. 375, 381 (1992).
Additionally, the Appeals Court has emphasized that a defendant’s mere presence at the crime scene isn’t enough to convict him of a joint venture. The defendant must actively participate in the commission of the crime. He must participate
to some extent in the commission of the offense… Participation may be proved by evidence that the defendant counselled, hired, or otherwise procured principals, rendered aid, assistance or encouragement or placed himself in a position where he could render aid in the commission of the crimes or assist in the escape from the scene ‘intentionally assisted the principal in the commission of the crime and that he did this, sharing with the principal the mental state required for that crime.’Commonwealth v. Chinn, 6 Mass. App. Ct. 714, 716 (1978).
Moreover, the defendant must share the principal criminal’s state of mind in regards to the crime:
The requirements for criminal liability in a joint enterprise are met by a showing that the defendant ‘intentionally assisted the principal in the commission of the crime and that he did this, sharing with the principal the mental state required for that crime.Id.
Mere acquiesce to the crime being commit in the defendant’s presence is not sufficient to find him culpable as a joint venturer:
Even if the defendant acquiesced in the commission of the crimes but did nothing more, that alone would not render [him] liable for her substantive offense.”Id.