Massachusetts Rules of Professional Conduct Rule 3.8: Special Responsibilities of a Prosecutor
The prosecutor in a criminal case shall:
(a) refrain from prosecuting a charge that the prosecutor knows is not supported by probable cause;
(b) make reasonable efforts to assure that the accused has been advised of the right to, and the procedure for obtaining, counsel and has been given reasonable opportunity to obtain counsel;
(c) not seek to obtain from an unrepresented accused a waiver of important pretrial rights, such as the right to a preliminary hearing, unless a court first has obtained from the accused a knowing and intelligent written waiver of counsel;
(d) make timely disclosure to the defense of all evidence or information known to the prosecutor that tends to negate the guilt of the accused or mitigates the offense, and, in connection with sentencing, disclose to the defense and to the tribunal all unprivileged mitigating information known to the prosecutor, except when the prosecutor is relieved of this responsibility by a protective order of the tribunal;
(e) exercise reasonable care to prevent investigators, law enforcement personnel, employees, or other persons assisting or associated with the prosecutor in a criminal case from making an extrajudicial statement that the prosecutor would be prohibited from making under Rule 3.6;
(f) not subpoena a lawyer in a grand jury or other criminal proceeding to present evidence about a past or present client unless:
(1) the prosecutor reasonably believes:
(i) the information sought is not protected from disclosure by any applicable privilege;
(ii) the evidence sought is essential to the successful completion of an ongoing investigation or prosecution;
(iii) there is no other feasible alternative to obtain the information; and
(2) the prosecutor obtains prior judicial approval after an opportunity for an adversarial proceeding;
(g) except for statements that are necessary to inform the public of the nature and extent of the prosecutor's action and that serve a legitimate law enforcement purpose, refrain from making extrajudicial comments that have a substantial likelihood of heightening public condemnation of the accused;
(h) not assert personal knowledge of the facts in issue, except when testifying as a witness;
(i) not assert a personal opinion as to the justness of a cause, as to the credibility of a witness, as to the culpability of a civil litigant, or as to the guilt or innocence of an accused; but the prosecutor may argue, on analysis of the evidence, for any position or conclusion with respect to the matters stated herein; and
(j) not intentionally avoid pursuit of evidence because the prosecutor believes it will damage the prosecution's case or aid the accused.
Adopted June 9, 1997, effective January 1, 1998. Amended December 9, 1998, effective January 1, 1999.
 A prosecutor has the responsibility of a minister of justice and not simply that of an advocate. This responsibility carries with it specific obligations to see that the defendant is accorded procedural justice and that guilt is decided upon the basis of sufficient evidence. See also S.J.C. Rule 3:08, Disciplinary Rules Applicable to Practice as a Prosecutor or as a Defense Lawyer. Applicable law may require other measures by the prosecutor and knowing disregard of those obligations or a systematic abuse of prosecutorial discretion could constitute a violation of Rule 8.4.
 Unlike the language of ABA Model Rule 3.8(c), paragraph (c) permits a prosecutor to seek a waiver of pretrial rights from an accused if the court has first obtained a knowing and intelligent written waiver of counsel from the accused. The use of the term "accused" means that paragraph (c) does not apply until the person has been charged. Paragraph (c) also does not apply to an accused appearing pro se with the approval of the tribunal. Nor does it forbid the lawful questioning of a suspect who has knowingly waived the rights to counsel and silence.
 The exception in paragraph (d) recognizes that a prosecutor may seek an appropriate protective order from the tribunal if disclosure of information to the defense could result in substantial harm to an individual or to the public interest.
 Paragraph (f) is intended to limit the issuance of lawyer subpoenas in grand jury and other criminal proceedings to those situations in which there is a genuine need to intrude into the client-lawyer relationship.
 Paragraph (g) supplements Rule 3.6, which prohibits extrajudicial statements that have a substantial likelihood of prejudicing an adjudicatory proceeding. In the context of a criminal prosecution, a prosecutor's extrajudicial statement can create the additional problem of increasing public condemnation of the accused. Although the announcement of an indictment, for example, will necessarily have severe consequences for the accused, a prosecutor can, and should, avoid comments which have no legitimate law enforcement purpose and have a substantial likelihood of increasing public opprobrium of the accused. Nothing in this Comment is intended to restrict the statements which a prosecutor may make which comply with Rule 3.6(b) or 3.6(c).
 Paragraphs (h) and (i), which do not appear in the ABA Model Rules, are taken from DR 7-106(C)(3) and (4), respectively. They state limitations on a prosecutor's assertion of personal knowledge of facts in issue and the assertion of a personal opinion on matters before a trier of fact, but under paragraph (i) a prosecutor may contend, based on the evidence, that the trier of fact should reach particular conclusions.
Corresponding ABA Model Rule. Model Rule 3.8, paragraphs (a)-(g) except for (c) (written waiver) and (f)(2) which is from former Model Rule 3.8(f)(2) and S.J.C. Rule 3:08, PF 15; paragraphs (h) and (i) are taken from DR 7-106 (C)(3) and (4). Paragraph (j) is taken from Rule 3:08, PF 7(b).
Corresponding Massachusetts Rule. See S.J.C. Rule 3:08, Standards Relating to the Prosecution Function.