A Butler County man who was released from a mental hospital just months before he tortured and killed his mentally disabled roommate pleaded guilty yesterday to first-degree murder.

Timothy James Caldwell, 30, will spend life in prison, plus 21 to 42 months for abusing a corpse and tampering with evidence, for the burning death of Jason Michael Ritzert, 30.

Butler County District Attorney Randa Clark agreed to the plea, giving up her plan to seek the death penalty for Mr. Caldwell.

His attorney, David DeFazio of Butler, said he had no choice but to advise his client to plead guilty.

Though Mr. Caldwell has spent years in a state mental hospital and Mr. DeFazio had hoped to use mental infirmity as a defense, his expert psychiatrist evaluated Mr. Caldwell and said he would be unable to testify that the defendant was not guilty by reason of insanity or guilty but mentally ill.

"I could get no help from my psychiatrist on this. I think there was real reason, because of the horrible circumstances of this case, that my client would have received the death penalty. I appreciate Miss Clark's offer to resolve this case in this way," Mr. DeFazio said.

Ms. Clark said Mr. Ritzert's family agreed with the plea bargain. They could not be reached for comment.

Mr. Caldwell is to be sentenced at 11 a.m. Thursday during a special session before Butler County Judge William Shaffer.

Pretrial pleadings are continuing for two co-defendants, Melissa Ann Adams, 25, and Russell Hilliard, 36, both of Butler. Ms. Clark did not speculate as to whether plea agreements will be reached in those cases. No trial dates are set.

Ms. Adams has been described as borderline mentally retarded. She is Mr. Caldwell's cousin. Mr. Hilliard was Ms. Adams' boyfriend.

The case was one of Butler County's more horrific and was described by the state police captain there, Robert Lizik, as "bizarre and brutal."

Mr. Caldwell confessed to authorities that he hit Mr. Ritzert and had burned his hands over a period of several weeks as "punishment" for stealing some pocket change. Then, one day in November 2005, he soaked Mr. Ritzert's shirt in lighter fluid, forced him into a bathtub, then set him afire.

Afterward, Mr. Ritzert's body was transported in a stolen meat truck to a garbage bin behind a warehouse in Summit Township and burned again, so badly that he had to be identified through dental records.

Ms. Clark called Mr. Caldwell's pending life sentence "some measure of justice for the Ritzert family."