Massachusetts Criminal Procedure Rule 3.1: Determination of Probable Cause for Detention
(Applicable to cases initiated on or after September 7, 2004)
(a) No person shall be held in custody for more than twenty-four hours following an arrest, absent exigent circumstances, unless:
(i) a warrant or other judicial process authorizes the person's detention,
(ii) a complaint has been authorized under Rule 3 (g), or
(iii) a determination of probable cause for detention has been made pursuant to subsection (b).
(b) A determination of probable cause for detention shall be made by an appropriate judicial officer. The appropriate officer shall consider any information presented by the police, whether or not known at the time of arrest. The police shall present the information under oath or affirmation, or under the pains and penalties of perjury. The police may present the information orally, in person or by any other means, or in writing. If presented in writing, the information may be transmitted to the appropriate judicial officer by facsimile transmission or by electronic mail or by such other electronic means as may be found acceptable by the court. The determination of probable cause for detention shall be an ex parte proceeding. The person arrested has no right to appear, either in person or by counsel.
(c) Where subsection (a) requires a determination of probable cause for detention, the police shall present the information necessary to obtain such determination to the appropriate judicial officer as soon as reasonably possible after the arrest, but no later than twenty-four hours after arrest, absent exigent circumstances.
(d) The judicial officer shall promptly reduce to writing his or her determination as to probable cause and notify the police. A copy of the written determination shall be transmitted to the police, by facsimile transmission or by other means, as soon as possible.
(e) The judicial officer shall apply the same standard in making the determination of probable cause for detention as in deciding whether an arrest warrant should issue. If the judicial officer determines that there is probable cause to believe the person arrested committed an offense, the judicial officer shall make a written determination of his or her decision which shall be filed with the record of the case together with all the written information submitted by the police.
(f) If there is not probable cause to believe that the person arrested committed an offense, the judicial officer shall order the person's prompt release from custody. The order and a written determination of the judicial officer shall be filed in the District Court having jurisdiction over the location of the arrest, together with all the written information submitted by the police. These documents shall be filed separately from the records of criminal and delinquency cases, but shall be public records.