BRENTWOOD, N.H. (CBS) - Investigators said Tuesday they still don't know what led to a horrific chain of events that ended with the death of a police officer and a home burned to the ground with a suspected gunman dead inside.
Brentwood Police Office Stephen Arkell, 48, was answering a domestic dispute call Monday afternoon when he was shot and killed as he arrived at the duplex.
The home then went up in flames, there was an explosion and it burned to the ground.
Senior Assistant Attorney General Jane Young confirmed at a news conference Tuesday afternoon that the suspected gunman, Michael Nolan, 47, was found dead in the garage after the fire was put out.
Young explained a timeline of Monday's events, saying it began when someone called police for a "verbal domestic dispute at 46 Mill Pond Road" at 4:02 p.m.
Watch: Investigators News Conference In Brentwood
The caller said Nolan was arguing with his father, 86-year-old Walter Nolan, who owned the home, which is in a neighborhood restricted to people 55 and older.
Eight minutes later, officer Arkell arrived and asked Walter Nolan if he could come inside. According to Young, Walter Nolan let Arkell in and, at about the same time, a witness heard "three volleys of gunfire."
An officer from nearby Fremont, Derek Franek, was then dispatched to the home and when he arrived he heard gunshots.
Officer Franek spoke to Walter Nolan outside and then handcuffed him for safety reasons and went into the house.
According to Young, Franek noticed a wall had been sprayed with bullets and he saw officer Arkell wounded on his back on the floor.
Young said Franek "was met with gunfire" so he ran from the front of house to the back, got outside and called for backup.
What happened next inside the home is still not clear.
More gunshots were heard, then a fire broke out, there was an explosion and the home burned down.
Young told reporters that after the fire was extinguished, Arkell's body was found in the rubble. It was removed Monday night and an autopsy determined he died from multiple gunshot wounds before the fire began.
Michael Nolan's body was found in the garage. The N.H. Attorney General said Tuesday afternoon that the cause and manner of Nolan's death is still unclear after an autopsy was performed and that more investigation will be done over the next several days.
She said investigators are still combing the scene and will be there at least through Friday, if not longer.
Young said it was too early to tell if Arkell had been ambushed.
"It certainly seemed that officer Arkell walked into a situation that he didn't anticipate," Young said.
She told reporters police had not been to the house before Monday's incident, but a neighbor reported hearing "verbal altercations" there in the past.
Hundreds attended a vigil for Officer Arkell at the Brentwood Recreation Center Tuesday night.
Residents who didn't even know the officer planned to attend.
"He was there to protect the whole community, the rest of this town, and anybody else. His life was on the line," Brentwood resident Susan Currier told WBZ-TV Tuesday.
Arkell, who was married and had two teenage daughters, had worked for the Brentwood Police Department for about 15 years as a part-time officer.
He helped coach the girls' lacrosse team at Exeter High School, where both of his daughters play.
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