A disciplinary proceeding for Cape and Islands prosecutor Laura Marshard continued this week in Boston, with Ms. Marshard testifying in her own defense.

Ms. Marshard is facing possible disciplinary actions over alleged professional misconduct in her handling of three criminal cases on the Vineyard. A complaint was filed last September by the Office of Bar Counsel, which investigates and prosecutes complaints against attorneys.

The complaint concerns three alleged instances of misconduct. The first relates to a superior court jury trial in 2014 involving an alleged assault in Oak Bluffs, during which the bar counsel complaint states that Ms. Marshard failed to disclose information from an interview with a witness. Another count centers on a case involving a 2014 bar fight in Oak Bluffs, in which Ms. Marshard allegedly met with a witness without seeking permission from his counsel first. A third count relates to a 2013 drug investigation in which a state police officer allegedly gave false testimony to a grand jury and Ms. Marshard did not correct him.

On Tuesday Ms. Marshard testified that she would have done one thing differently related to meeting with a witness without a police officer present, according to the Cape Cod Times.

The complaint filed by Bar Counsel describes a jury trial in Dukes County superior court that involved an alleged assault during a brawl at the Ritz in March 2013. Defendants Patrece Petersen and Darryl Baptiste faced assault charges and Mr. Petersen was charged with murder; both men were acquitted by the jury. Ms. Marshard prosecuted the case.

The complaint alleges that Ms. Marshard failed to disclose information she obtained in an interview with the bartender at the Ritz. On Tuesday Ms. Marshard said that was a mistake, according to the Cape Cod Times, and acknowledged it was normal conduct to have a police officer present during interviews with witnesses.

During questioning by her counsel, Elizabeth Mulvey, Ms. Marshard defended herself against the other allegations.

The proceeding began in May and is expected to continue June 26. Previous witnesses have included Vineyard defense attorneys and district court clerk magistrate Liza Williamson.

Disciplinary cases against prosecutors are considered rare.