SACO — Maine State Police will not charge the Saco resident who shot a New Hampshire man to death last September, saying the shooting was self-defense.

For months, friends and relatives puzzled over why Michael Burns, a 54-year-old computer network repairman, went to a duplex at 26 Nye St. after 1 a.m. on Sept. 30, 2017, and ended up shot three times and killed.

State police now say Burns, who was in town for work, went to the home looking for sex after answering a Craigslist advertisement. Steve McCausland, spokesman for the Maine Department of Public Safety, said Burns got into a confrontation on the porch and was shot in self-defense by a resident.

But questions about what happened that night still linger, and the case is now being handled by Saco police and the York County District Attorney’s Office. While there won’t be a criminal charge for the fatal shooting, authorities could still press charges related to other aspects of conduct that night.

McCausland said Burns arrived at the home and paid a woman $100. But, he said, the two did not have sex and an argument erupted. Burns went outside to his truck and returned with a knife, McCausland said.

“He was upset, had gone back to his vehicle, came back with a knife, and got into a confrontation with a woman,” McCausland said. “The man who resides at the home then fired at Burns and shot and killed him.”

At the time of the shooting, police said there were three people in the apartment before the death, but police have not said who they were.

McCausland would not provide further details, including what led to the argument and how the gunman was involved. A deputy attorney general also declined to discuss the details, saying it could still be the subject of a prosecution by local authorities.

Police also have declined to name the man who killed Burns because he won’t be prosecuted for the death.

However, the owner of the building where the shooting happened identified the gunman as Christopher Boure, 43, a longtime tenant of the first-floor unit.

Remi Caron told the Press Herald that he has rented to Boure for about six years and in that time he has not had any problems with Boure, who is a self-employed house painter. Caron said he hired Boure to paint the Nye Street home in exchange for a rent discount.

After the shooting, Caron called his tenant to ask about what had happened. Caron said Boure identified himself as the gunman and described in broad strokes what had occurred.

“He said somebody came to the house,” Caron said. “It wasn’t necessarily framed as an invasion. Someone came to the house and was causing a ruckus and was trying to get in forcefully and was very vocal, and when Chris was trying to remove him from the property there was a knife and he felt that he needed to defend himself.”

Caron said Boure did not mention anything about prostitution or anyone else being in the unit at the time of the shooting.

Multiple attempts by the Press Herald to contact Boure failed. He did not respond to messages sent to him by email or by Facebook, and he did not reply to previous attempts to reach him in October 2017 after the killing. A reporter visited his home and knocked on the door twice last week, and no one answered.

A neighbor described him as a friendly firearms enthusiast who sometimes carried a holstered handgun as he mowed his lawn.

“You couldn’t ask for a better guy,” said Marc St. Ours, who lives across the street. “I’ve never seen him upset. We borrowed each other’s tools and worked on our snowblowers and lawnmowers together.”

Following his death, Burns’ friends and family reeled with questions about what happened to the person they knew as a deeply devoted father and self-made businessman. Burns was a well-known figure in New Hampshire Boy Scout circles, where he was a troop leader.

Mike Burns, Burns’ adult son, said in an interview that police briefed the family in the spring about what happened and how the investigation was proceeding. But the information about prostitution and the other two people in the home was new and raises more questions, Burns said.

Mike Burns said he was told that in addition to the knife, police found a bag of his father’s tools at the home, and there is no clear explanation as to why he would have needed them. It is also still unclear how long Burns was at the home or whether Boure knew that prostitution was allegedly taking place there.

Police told Burns that Boure had some kind of slash or knife injury to his arm, apparently supporting the finding of self-defense. But Burns said he still has questions about how things played out that night.

“I want to see some justice or accountability come from this,” said Burns, who now lives in Colorado. “This behavior is so uncharacteristic of (my father).”

According to police, Burns was shot three times on the enclosed front porch of the home, including at least once in the head. The person who shot him then called 911, police said immediately after the death.

“In essence, it was self-defense,” McCausland said.

Deputy Attorney General Lisa Marchese, who is chief of the criminal division that would have prosecuted any homicide charges, said in an email that she could not comment on the details of the case because it is still being evaluated for other charges. But she agreed the shooting was self-defense.

“In this particular case, it was determined that the person entered the home without a license or privilege to do so and that deadly force was necessary in order to prevent the infliction of bodily injury in the dwelling place,” Marchese said in the email. “Fortunately, these types of cases are rare. When the facts are clear cut, the decision is made not to prosecute.”