The Pittsburgh Tree of Life synagogue mass shooter, who was convicted this month in the 2018 killings of 11 people in the nation’s deadliest antisemitic attack, had a history of psychotic symptoms that impaired his brain, his defense attorney argued Monday.

In the penalty phase of the federal trial, which began Monday, prosecutors are seeking a death sentence for Robert Bowers, who was found guilty on 63 criminal counts on June 16. But Bowers’ defense team said the gunman has psychotic, delusional, and paranoid symptoms that make him ineligible for the death penalty.

Defense lawyer Michael Burt told jurors that Bowers has a history of suicide attempts and has had brain impairments since childhood, including symptoms of epilepsy and schizophrenia. Medical tests found Bowers’ brain to be “structurally deficient,” Burt added.

Prosecutors countered the defense team’s argument and said Bowers had a clear intent to kill everyone he encountered in Pittsburgh’s Tree of Life synagogue on Oct. 27, 2018.

“He came to kill,” said prosecutor Troy Rivetti. “The defendant entered the Tree of Life synagogue, a sacred place to gather and pray, and he murdered 11 innocent worshippers.”

Defense focuses on Bowers’ mental health

While the defense admitted Bowers carried out the attack, Burt told the jury Monday that Bowers’ brain impairments caused him to be delusional and the jury is unable to impose a death sentence on him because of his inability to form a requisite level of intent. “Those delusional beliefs led directly to the horrible events of October 27, 2018,” Burt said.