An Alton man who kidnapped his ex-girlfriend and killed a Greenbush man on Sunday died Monday morning from a self-inflicted gunshot wound, according to the Maine State Police.

Police have deemed the incident that started in Bradley and ended in Connecticut a murder-suicide and yet another case of domestic violence in the state.

Eric Niles, 19, of Alton confronted his ex-girlfriend Kristin Cates, 18, and Blake Mishou, 20, of Greenbush in the bedroom of a home in Bradley early Sunday morning, police said. The two were in bed together at the Bradley home of Cates’ mother and stepfather, Jill and Randall Rand, when Niles entered the room, according to Maine State Police spokesman Stephen McCausland.

Niles killed Mishou and then abducted Cates in a pickup that he had stolen from his grandfather.

Staff from the state medical examiner’s office said Monday that an autopsy on Mishou had been scheduled for today.

Niles and Cates reached Connecticut before being spotted in the stolen truck just before 6 p.m. Sunday on southbound Interstate 95.

When a Connecticut state trooper tried to pull the vehicle over, Niles, who was in the passenger seat, shot himself in the head. Cates was driving the black Chevrolet Silverado pickup truck with a black cap and canoe rack. Niles died of his injuries Monday morning. An autopsy was scheduled to be completed in the afternoon, but no details were available. McCausland said he didn’t know how Niles had gained possession of the gun.

Niles had been the subject of a New England-wide alert issued Sunday by authorities in Maine, because he was characterized as a person of interest in Mishou’s death.

Cates recently had broken up with Niles, according to Maine State Police detectives, and she had taken a protection from abuse order out on him although he still was listed as her boyfriend on her MySpace page on the Web.

Niles had experienced minor run-ins with police in the past and in March was arrested for assault, according to Penobscot County Sheriff Glenn Ross. Niles posted bail, but was arrested a second time April 15 for violating his bail conditions. He posted bail again after appearing at 3rd District Court in Bangor.

Maine State Police detectives drove to Connecticut Sunday and interviewed Cates. They determined that she had gone with Niles against her will. Cates’ parents drove to Connecticut to bring their daughter back to Maine. Cates wasn’t injured, and no charges have been filed against her, McCausland said Monday.

The Associated Press contributed to this story.

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