A hearing is under way in Boston in a disciplinary case against a Vineyard prosecutor over her alleged professional misconduct in criminal cases.

Cape and Islands assistant district attorney Laura Marshard, who lives in West Tisbury and frequently handles cases in Edgartown district court and Dukes County superior court, is facing possible disciplinary action pending the outcome of hearings before the state Board of Bar Overseers.

Last September the Office of Bar Counsel, which investigates and prosecutes complaints against attorneys, filed a complaint against Ms. Marshard for alleged professional misconduct in her handling of three different criminal cases in Edgartown. Acting through her attorney, Ms. Marshard has refuted the charges.

Vineyard defense attorney Rob Moriarty testifies at hearing Wednesday. — Merrily Cassidy/Cape Cod Times

Disciplinary cases against prosecutors are considered rare.

Hearings began on Wednesday this week and are scheduled to continue next Monday, Tuesday and Wednesday.

Ms. Marshard is represented in the matter by Elizabeth Mulvey.

Several Vineyard defense attorneys and police officers are being called as witnesses in the proceeding, along with the Hon. H. Gregory Williams, a retired district court judge, and Edgartown district court clerk magistrate Liza Williamson. Witnesses called this week included Rob Moriarty, a Vineyard defense attorney.

The complaint describes three alleged instances of misconduct in cases in 2013 and 2014. The first relates to a 2014 superior court jury trial involving an alleged assault in Oak Bluffs. In an unusual step during the trial, the Hon. Richard Chin halted proceedings to admonish Ms. Marshard for misconduct, saying that she had improperly hindered the defense. The bar counsel complaint focuses on this and other parts of that trial, including an alleged failure to disclose information from an interview with a witness. The complaint also claims Ms. Marshard made statements to the court that were without a good faith basis and attempted to interfere with the defendants’ ability to present their case.

Another count centers on a case involving an alleged fight in 2014, in which Ms. Marshard allegedly met with one of the men involved without seeking permission from his counsel to do so.

A third count relates to a 2013 drug investigation in Oak Bluffs in which a state police officer allegedly gave false testimony to a grand jury. The complaint alleges that Ms. Marshard knew the testimony was false but did not correct it, or if she wasn’t aware the testimony was false she was not adequately prepared to present the matter.

The Board of Bar Overseers is an independent administrative body that investigates and evaluates complaints against attorneys in Massachusetts.

Cape and Islands district attorney Michael O’Keefe has said he fully backs Ms. Marshard.