Massachusetts Guide to Evidence 2025 Edition MA R EVID § 104

(a) In General. The court must decide any preliminary question about whether a witness is qualified or competent, a privilege exists, or evidence is admissible. In so deciding, the court is not bound by the law of evidence, except that on privilege.

(b) Relevance That Depends on a Fact. When the relevance of evidence depends on whether a fact exists, proof must be introduced sufficient to support a finding that the fact does exist. The court may admit the proposed evidence, de bene, on the condition that the proof be introduced later. Evidence so admitted is subject to a motion to strike if that proof is not forthcoming.

(c) Conducting a Hearing So That the Jury Cannot Hear It. The court must conduct any hearing on a preliminary question so that the jury cannot hear it if

(d) Cross-Examining a Defendant in a Criminal Case. By testifying on a preliminary question, a defendant in a criminal case does not become subject to cross-examination on other issues in the case, except issues that affect the witness's credibility.

(e) Evidence Relevant to Weight and Credibility. The law stated in this section does not limit a party's right to introduce before the jury evidence that is relevant to the weight or credibility of other evidence.