AUBURN – James Michael Peters died of a shotgun wound to his abdomen after being shot by a law enforcement officer, the state Medical Examiner’s Office ruled on Monday.

Police say Peters shot and killed his mother, Margaret Peters, 70, with a shotgun Friday morning at the home they shared at 1806 Minot Ave. When Auburn officers arrived around 10:30 a.m., they found Margaret Peters’ body in the driveway. Believing that James Michael Peters was in the home with at least one weapon – an AK-47 assault rifle – local police closed off the street and called in a state police tactical team.

Peters exchanged gunfire with police at 5:25 p.m. during his 17-hour standoff with police on Friday. Investigators had been working under the assumption that Peters was killed by a member of the Maine State Police tactical team during that exchange. That assumption was based on the position of Peters’ body, which was found slumped next to a window through which he had fired at police, prompting a return of fire.

Stephen McCausland, a spokesman for the state Department of Public Safety, said the gunfire followed the launching of tear gas canisters into the house by police.

During the exchange, more than a dozen shots were heard by reporters near the scene on Minot Avenue. Only two state troopers – Lucas Hare and Douglas Cropper – fired their weapons then, according to David Loughran, spokesman for the state Attorney General’s Office.

That office is investigating the shooting, as it does when police officers use deadly force.

By the time the standoff ended, nearly every window in the house had been shot out and the garage door had been bashed in by a state police armored vehicle. Police tactical teams stormed the house at about 3 a.m. Saturday. That’s when they found Peters’ body.

Over the course of the siege, neighbors were evacuated while a hostage negotiator tried to get Peters out of the house, speaking to him through a bullhorn and offering him cigarettes and food. Police also attempted to call Peters more than 100 times on the home’s telephone. Peters never answered, except through his exchange of gunfire with police.

During the standoff, police lobbed dozens of canisters of tear gas and percussion grenades into the home.

Police found multiple weapons in the home, including a shotgun that police say Peters used to kill his mother, and an AK-47 assault-style rifle, according to McCausland.

The Associated Press contributed to this report.

James Michael Peters’ body will eventually be released for burial. A spokesperson for the Medical Examiner’s Office wasn’t sure when, or if, a toxicology report would be done.

The Associated Press contributed to this report.