LYNN – Authorities are keeping close wraps on details surrounding the fatal St. Patrick’s Day shooting of a Lynn man that followed an 8-hour standoff with a State Police tactical team.An autopsy was performed Tuesday on Robert Mangiafico, 37, who apparently died of gunshot wounds in the driveway of a Brookvale Street home.”We have not been informed of any autopsy results,” Steve O’Connell, spokesman for Essex County District Attorney Jonathan Blodgett, said Tuesday. The autopsy was performed at the state Office of the Medical Examiner in Boston but the results were not expected until later this week, he said.State Trooper Elaine Gill, head of the major crimes investigative unit assigned to Blodgett’s office, spent Tuesday at State Police headquarters in Framingham interviewing members of the STOP team involved in the standoff with Mangiafico, according to O’Connell.”She’s interviewing the STOP team and people who were there,” O’Connell said. “The district attorney does not want to release any information until we have all the facts.”The incident began at approximately 9 p.m. Sunday when Mangiafico assaulted his girlfriend, Rose Hirst, inside their 27 Woodman St. apartment. After the violence subsided, Hirst asked a neighbor to call police because Mangiafico had nearly strangled her and pointed a handgun at her face.With Lynn police en route, Mangiafico and Hirst left the apartment and headed toward a local market to buy dog food, according to Hirst. On the way home, Mangiafico got out of the car and started walking. Police spotted him on Center Street. A foot chase through the neighborhood ended near the corner of Tacoma and Brookvale streets when Mangiafico ducked into a driveway.Lynn police surrounded the address and evacuated the closest neighbors. As the standoff entered its third hour, a State Police tactical team was requested. Just after 5 a.m. Monday flash-bang grenades and gunfire rang out. A few minutes later, Mangiafico was declared dead at Union Hospital. Since then, police have declined to explain how the shooting began or who fired.Jack and Diane Barton watched the action unfold from a window of their Brookvale Street home, which overlooks the driveway where Mangiafico was crouched behind a car, occasionally talking on a cell phone as he pressed what appeared to be long-barreled revolver against his neck.The Bartons retreated to the second floor of their home and camped on a sofa with their Dalmatian dog Sparky. “The only thing we were concerned about was stray shots. We could look right down on him and he seemed like a man in pain,” Jack Barton said. “You could tell he was hurting.”According to the Bartons, police were patient and repeatedly tried to get Mangiafico to drop the gun and surrender. “They even gave him cigarettes,” said Jack Barton, noting the man was dressed in a hooded jacket or sweatshirt, long pants and boots. “They were talking to him all night long. From what I saw, they gave this guy his due. After all, daylight was coming with people going to work and school. They had to do something. They gave this guy every opportunity to walk way.”Mangiafico held the handgun to his neck through most of the night and threatened to pull the trigger.The Bartons eventually went to sleep with the standoff unresolved but were awakened by what they believed were exploding grenades just after 5 a.m.Jack Barton said his apartment was bathed in white light during the explosions. Seconds later, the air was filled with shouting and screaming, then silence, he said.”The two flash bangs created a bright white light and then there were a few other pops going off. We could see a lot of lights,” he said.Diane Barton said she heard a police officer shout that Mangiafico had shot himself in the throat and to summon the medics.”He was bleeding from the throat,” she said.When the smoke cleared and dawn finally broke, the couple could see what looked like pepper spray pellets and other residue in the driveway.”The police did e