PITTSBURGH (KDKA) — The man accused in the murder and dismemberment of his roommate in Carrick last year will spend the rest of his life behind bars.

John Dickinson, 43, has been sentenced to life in prison without parole for reason of mental illness. He pleaded guilty Monday morning in court.

Pittsburgh Police detectives say when they interviewed Dickinson in the summer of 2018, he admitted to killing Kevin Thompson and then dismembering his body.

According to police, Dickinson and 46-year-old Thompson were living together on Parkfield Street in Carrick. Shortly after Thompson’s mother reported him missing on May 31, 2018, detectives discovered his remains, both in the basement of the house and in a shed.

Investigators say blood-spattered walls indicated a violent struggle between the men spanned from the second floor to the basement.

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A forensic psychologist took the stand Monday during the sentencing.

She said after evaluating Dickinson for hours, she diagnosed him as a traumatized schizo-psychopath.

The forensic psychologist said she evaluated him back in March. She said that he was not in control of himself when he killed Thompson. It was in June of 2018 when Dickinson beheaded Thompson.

It was a gruesome scene for investigators. They say Thompson died from blunt force trauma and multiple stab wounds. Parts of his body were wrapped in trash bags, including various limbs, and a severed head inside a shed.

The forensic psychologist said that Dickinson has a family history of mental illness and has even referred to himself to her as a “wolf.” When she was asked about what happened in June of 2018, she said that it triggered a “homicidal mania” for Dickinson.

While in court, Dickinson read a letter apologizing to his family and Thompson’s family. When he was asked if he had anything else to say, he said no, “I’m ready to go back to jail.”