Wayne Kozak, of Eden, will learn his fate next month for murdering his mother, 79-year-old Mary Kozak, on April 20, 2017.
Under a deal with the district attorney announced Monday, Kozak, 50, pleaded guilty to Manslaughter in the First Degree. He was originally charged with Murder in the Second Degree.
Erie County District Attorney John Flynn says Kozak has suffered from extreme emotional disturbances since at least 2011. He says the two had been arguing in their home on East Eden Road.

"What the nature of the argument was, I don't know. But he had an argument with his mother and it obviously got to the point where he felt the need to shoot his mother," Flynn said.
Flynn says the lesser charge includes a higher minimum sentence because Kozak is not only a threat to society, he is a threat to himself.
"After he shot his mother, he then fled to Erie, Pennsylvania. Fortunately he did not use the gun at all in the Erie, Pennsylvania hotel room. But he obviously was planning on shooting himself, we believe. He also, when he was in the Erie County Holding Center, tried to swallow a toothpaste tube to kill himself," Flynn said.
Kozak faces 20 to 25 years in prison when he is sentenced November 7.