Advertisement Fallen Brentwood officer ambushed by gunfire before explosion Officer Stephen Arkell killed when he entered home Share Shares Copy Link Copy

A Brentwood police officer was ambushed by several rounds of gunfire as he entered a home minutes before it exploded Monday, officials said.Slideshow: Photos from the sceneOfficer Stephen Arkell, 48, was shot and killed by Michael Nolan, 47, when he responded to a call about an argument between Nolan and his father, Walter, 86, at 46 Mill Pond Road, Attorney General Joseph Foster said.Watch reportFremont police Officer Derek Franek, a backup officer who went to help Arkell, entered the home and saw Arkell lying on his back near a wall "sprayed with bullets," Assistant Attorney General Jane Young said, adding Arkell was already deceased."The courage that he had to walk into that situation alone, to try to help his fellow officer is heroic," Young said.The younger Nolan set the house on fire, and it was ripped apart by a massive explosion at about 5:50 p.m., investigators said.Investigators believe Michael Nolan was killed by the fire or the explosion. What are believed to be his remains were found in a burned out area of the home's garage.Authorities said police had never been called to the house before and that Nolan had no criminal record.Walter Nolan was treated at a local hospital for bruises and is being cared for by his daughter.Arkell, a 15-year veteran of the department, was a married father of two teenage girls."We did hear the explosion. There were helicopters flying around and we heard a boom. We heard several pops after that," said neighbor Susan Currier. Watch video of home explosion"And (officers) started taking rifles out of their trunks, and I could hear them loading. And then I heard 10, 12, 15 shots maybe," one neighbor said."It was a very loud noise and it was scary. I didn't feel a rattle or anything, but it was a shocking sound to hear in our little community," Currier said.Gov. Maggie Hassan ordered that flags be flown at half-staff in Arkell's honor. A 15-year veteran of the department, he was a married father of two teenage girls."Officer Arkell bravely answered the call of duty and made the ultimate sacrifice, a heroic demonstration of his commitment to the safety of his fellow citizens," Hassan said. "Like so many of our first responders do on a daily basis, Officer Arkell courageously put his life on the line to protect others, and in doing so, was tragically taken far too soon.""It was just tragic. I feel so awful for the police officer and his family. My heart goes out to him. My prayers go out to him and his family," Walter Nolan's son-in-law, Richard Florino, said. "May God take care of them and ease their pain. That's what we're concerned about. We've had family members that are police officers and understand that situation."One of Arkell's daughters will graduate from Exeter High School next month.