OAKLAND (CBS SF) — A day after John Lee Cowell was convicted of first-degree murder for the fatal stabbing of Nia Wilson at the MacArthur BART station in Oakland in 2018, the attorneys in his trial argued on Wednesday afternoon about whether he was legally sane at the time of the attack.

The sanity phase of the trial for Cowell, a 29-year-old transient man with a history of mental illness, was unusually short after defense attorney Christina Moore didn’t present any witnesses on his behalf.

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While Moore sought to present the testimony of a mental health expert, presiding Alameda County Superior Court Judge Allan Hymer ruled at a hearing outside of the presence of jurors on Wednesday morning that the expert couldn’t testify.

In the afternoon session in front of jurors, Moore and Alameda County prosecutor Butch Ford proceeded directly to present their closing arguments to the same jurors who delivered their guilty verdicts against Cowell late Tuesday afternoon after deliberating for only a few hours.

On Wednesday, Cowell was convicted of first-degree murder for fatally stabbing 18-year-old Nia Wilson at the MacArthur station in Oakland at about 9:35 p.m. on July 22, 2018. He was also convicted of premeditated attempted murder for stabbing Wilson’s sister, Letifah Wilson, who was injured but survived the attack.

In addition, jurors found true a special circumstance allegation that Cowell murdered Nia Wilson by lying in wait for concealing his intent and then killing her by taking her by surprise.

Cowell, who pleaded not guilty by reason of insanity, could face life in prison without the possibility of parole. But if jurors rule that he was insane at the time of the attack, he would serve his sentence in a state mental hospital instead of prison.

Tensions ran high throughout the emotionally charged trial. On Monday, at one point Moore asked jurors if they could believe Ford’s allegation that she was a co-conspirator with Cowell to magnify his mental illness. Some members of the gallery, which was packed with Wilson’s family members and friends, called out “yes.”

Moore asked Alameda County Superior Court Judge Allan Hymer to admonish the audience and turned to the spectators and said, “This isn’t about you.”

On the first day of the trial, Cowell was removed from the courtroom following an outburst during the prosecution’s opening remarks. The judge first admonished Cowell for speaking out to defend himself, telling Cowell to keep quiet and ultimately having Cowell removed when he continued.

When Cowell took the witness stand, he told jurors he hears voices from alien technology implanted in his ear in a series of bizarre ramblings.

Cowell sparred with his attorney during her questioning, testifying that he heard voices in his head that came from alien technology implanted in his ear with aliens using a radio to communicate with him.

He also referred to people wearing “fake skin” and “skin suits,” insisting that the Wilson sisters were aliens that were threatening him. Cowell also said the sisters had kidnapped his grandmother and were threatening to hurt her.

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Cowell said that the sisters were standing over him on the BART train and staring him down and that attacking them was the only way to save his grandmother.

Hymer told jurors on Wednesday that the defense has the burden of proof in the sanity phase in trying to establish that Cowell has a mental disorder or defect and that he was incapable of understanding the nature of his act and that it was morally or legally wrong.

Moore said the record in the guilt phase of Cowell’s trial shows that “he was disconnected from reality and was unable to understand that his act was morally wrong.”

Moore said, “The act was senseless and unprovoked and speaks to what was going on his mind.”

The defense lawyer said Cowell has a history of mental disorders, suffers from schizophrenia and wasn’t taking his medications at the time of the stabbing because he was hearing voices telling him that his pills were poisonous.

Moore said Cowell is “paranoid in nature” and because of that he has refused to meet with doctors who could help him better demonstrate the seriousness of his mental illness.

Ford admitted that Cowell suffers from mental health issues but argued that the defense failed to prove that Cowell didn’t understand that the stabbing was morally and legally wrong.

Ford said Cowell’s actions after the stabbing indicate he knew what he had done was wrong because he misdirected police who responded to the scene, discarded his knife and change his clothes.

Ford said, “If you believe what you’re doing is right, there’s no reason to flee.”

Cowell was absent from most of his trial, either because of outbursts or because he’s refused to come to court, but he was present during the sanity phase arguments.

Jurors began deliberating late Wednesday afternoon.

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