JACKMAN, Maine — Two U.S. Border Patrol agents were justified in using deadly force when they killed a 75-year-old man during a confrontation at his home in June, Maine Attorney General William J. Schneider said Tuesday.

Border Patrol Agents Jamie Tierney and Chris Demanski returned fire after the resident, Charles Robinson, fired a 12-gauge double-barrel shotgun round that peppered Tierney with pellets. Tierney was about 15 feet from Robinson, who was standing behind a barrier, when Robinson fired.

Tierney already had ordered Robinson to show his hands, Schneider said.

“It was reasonable for the agents to believe that unlawful deadly force was being used against them, and it was reasonable for the agents to believe that it was necessary for them to use deadly force to counter that use of deadly force,” Schneider said in a report released Tuesday.

Before they entered the house, the uniformed agents had repeatedly announced themselves as law enforcement officers who wanted to see Robinson, who they knew could be armed. Robinson had been arrested about three months earlier, the attorney general said.

The agents had come in response to a call from Robinson’s girlfriend at his home on Long Pond Road at about 7:30 p.m. on June 23. They believed they were confronting a domestic incident, possibly a violent one, in which the girlfriend might have been injured, Schneider said.

Dispatchers had told them that the female caller was in a verbal argument with Robinson and needed an ambulance because he was very drunk and had fallen. They also knew he had weapons in the home, and that a call from the girlfriend to the Jackman Regional Health Center had ended abruptly, Schneider said.

Tierney’s single .40-caliber bullet killed Robinson when it punched through his upper left arm and into his chest. Robinson’s blood-alcohol content when he died was 0.15, almost twice the legal limit of 0.08 for driving, the autopsy showed.

In more than 80 incidents reported over the last 20 years, no Maine law enforcement officer has been ruled to have used deadly force inappropriately by the attorney general’s office ― an unlikely seeming statistic until, according to one FBI expert, the high degree of training employed by Maine law enforcement is considered.

Deadly force is justified under Maine law in self-defense or the defense of others when two requirements are met. The threatened individual must actually and reasonably believe that unlawful deadly force is imminently threatened against him or against someone else, and the individual must actually and reasonably believe that deadly force is necessary to counter that imminent threat, Schneider said.

As is common with officers responding to incidents that they themselves haven’t witnessed, Tierney and Demanski were interpreting imperfect information relayed through dispatchers. In this case, it was information from Robinson’s girlfriend as heard and relayed by a health center worker who had taken her call and then called the Somerset County Sheriff’s Office and the U.S. Border Patrol office in Jackman, Schneider said.

The two agents answered the call, Schneider said, because they knew that Somerset County deputies were at least an hour from Jackman. When they arrived at Robinson’s home, they didn’t know that the girlfriend had left and was at the health center, Schneider said.

The two agents approached the front door on foot from different directions. They saw and heard nothing unusual after yelling that they were law enforcement officers and wanted the person inside the residence to show himself or they would come inside, Schneider said.

After Robinson was shot, the agents retreated from the house until the state police tactical team arrived. They later learned that the shotgun had a round left in one barrel, Schneider said.