A former U.S. Border Patrol agent who gunned down a man during an off-duty noise-related confrontation near his Hemet home was convicted today of second-degree murder.

John Richard Demery, 42, shot 27-year-old Adam Thomas of Moreno Valley in the predawn hours of Nov. 8, 2014.

Following six days of deliberations, a Murrieta jury found Demery guilty of the murder count, as well as sentence-enhancing gun and great bodily injury allegations. Riverside County Superior Court Judge John Monterosso scheduled sentencing for March 3 at the Southwest Justice Center.

Demery, who's being held at the Southwest Detention Center, is facing 40 years to life in state prison.

According to the District Attorney's Office, Demery had been disturbed on several occasions by a vehicle, its tires screeching, speeding through his neighborhood in the area of Cornell Street and Toledo Drive.

The ex-patrolman was first bothered by the noise on the evening of Nov. 7, 2014, and called Hemet police, who told him they would handle it, prosecutors said.

About 12:45 a.m. on Nov. 8, the defendant heard the sound again and decided to investigate, taking his flashlight, camera phone and personal handgun, later telling investigators that he anticipated trouble.

Demery wanted to take a picture of the license plate of the car causing the disturbance, prosecutors said. Instead, he ended up in a heated verbal altercation with Thomas, who had parked his car on Cornell.

During the argument, Demery pulled his pistol and shot Thomas five times, investigators said. According to prosecutors, Thomas was unarmed but had taken a fighting stance -- though he never swung or tried to get physical with the defendant.

The victim died at a hospital a short time later, and Demery was taken into custody without incident.

He was placed on unpaid leave in the months immediately following the shooting but was discharged in 2015. According to the Department of Homeland Security, he was an agent for six years, working much of that time at the Border Patrol's Murrieta station.