“I have completed the portion of the investigation the District Attorney’s Office will do,” Hampden District Attorney Mark G. Mastroianni said Wednesday.
The district attorney had state police attached to his office look into the matter.
Meanwhile, Christina A. Sterling, spokeswoman for the Boston office of the U.S. Justice Department, which oversees the U.S. Attorney’s office, said her department neither confirms nor denies the existence of an investigation.
According to Mayor Gregory C. Neffinger, someone wrote a letter either to the U.S. Attorney’s Office or the Hampden District Attorney’s Office alleging an incident involving Capt. Daniel O’Brien and a woman in police custody in the fall.
O’Brien was placed on administrative leave without pay during the last weeks of the administration of former Mayor Edward J. Gibson, who stepped down in January, according to Neffinger. The mayor said he does not know details of the complaint.
In mid-January Mastroianni said he hoped to wrap up the investigation in several weeks. The district attorney said the investigation involves an allegation of misconduct that raises the issues of civil rights violations and police brutality.
Police Chief Thomas Burke could not be reached for comment Wednesday.
One of five police captains, O’Brien has a salary of approximately $91,000. He has been on the force since 1988. The Police Department has been asked to not do its own internal investigation.