KINGSTON, N.Y. (NEWS10) — An Ulster man is doing time in Ulster County Jail after a judge convicted him of a deadly shooting, that happened back in September 2021. Gregory Thayer, 50, was convicted on Wednesday in a non-jury trial before Judge Bryan Rounds in Ulster County Court.

Judge Rounds ruled that Thayer had committed second-degree murder in 2021. However, Thayer was mentally unstable at the time, so he could only be charged with first-degree manslaughter, the Judge said.

Thayer was also convicted on a single charge of criminal possession of a weapon in the second degree, a violent felony. The manslaughter conviction carries a sentence of up to 25 years in state prison, and the weapons charge carries a sentence of up to 15 years in prison, which can be imposed consecutively for a total of 40 years.

According to evidence presented at trial, on Sept. 29, 2021, Thayer got into a heated argument with Bruce Swierc, of California. Thayer got so mad that he left the kitchen where the two had been hanging out, went up to his bedroom, got a gun, and came back to the kitchen where he shot Swierc in the back of the head. After shooting Swierc, Thayer called his sister, Stephanie Thayer, instead of 911 or police.

Bruce Swierc lived in California with his wife and family. He was visiting the Hudson Valley where he had grown up to console his mother, a Rhinebeck resident, who had recently lost her partner. Before returning to California, he had planned to spend a few days more to see relatives and Thayer, whom he had been close with since childhood. Swierc was 48 years old.

Ulster County District Attorney David Clegg commended the work of the Town of Ulster Police Department and the State Police on the case. He added that the work of law enforcement and the prosecution team focused on the substance of the case rather than the “shiny objects all around.”

Following Thayer’s conviction, Chief ADA Emmanuel Nneji requested that he be remanded to the Ulster County Jail. Judge Rounds granted the request, sending Thayer to jail without bail until sentencing. He will be sentenced on July 21, in Ulster County Court.