Criminal proceedings commence in district court when a police officer or, on rare occasions, a private citizen files a complaint against the defendant.  See Mass. R. Crim. R. Rule 3(a).

Whoever files such a complaint must provide a written statement which “convey[s] to the court the facts constituting the basis for the complaint.” Mass. R. Crim. P. Rule 3(g)(1).

The written statement must adequately describe the alleged offense and state the legal grounds for each and every charge against the defendant.  This requirement is based in the Massachusetts Constitution which reads:

No subject shall be held to answer for any crimes or offence, until the same is fully and plainly, substantially and formally, described to him.

Article 12 of the Massachusetts Declaration of Rights.

In most cases, the written statement provided to the court is simply the police report.  These reports are often hastily prepared and sometimes lack important details which the defendant is entitled to.  In such cases, either the defendant or the judge may seek a “bill of particulars” from the prosecution.

a defendant may request or the court upon its own motion may order that the prosecution file a statement of such particulars as may be necessary to give both the defendant and the court reasonable notice of the crime charged, including time, place, manner, or means.

Mass. R. Crim. P. Rule 13(b)(1).

If the defendant opts to file such a motion, he must abide by the requirements for pretrial motions set out in Rule 13(a). 

Additionally, the defendant should keep in mind that the “particulars” provided by the prosecution following such a motion become part of the charging documents and, consequently, may be read to the jury if the case goes to trial.  See Commonwealth v. Doherty, 353 Mass. 197, 211-12 (1967).