John Lee Cowell appealed his first-degree murder conviction in the fatal 2018 stabbing of Nia Wilson at an Oakland BART station, but the First Appellate District of California did not buy his attorneys’ claims of an insanity defense.

You may recall the 2018 killing of Nia Wilson at the MacArthur BART Station, where then-29-year-old transient man John Lee Cowell stabbed and killed Wilson, and also stabbed her older sister Letifah in the neck (she survived). Cowell’s killing of Wilson was caught on video, so his guilt was never really in question. But he pleaded not guilty by reason of insanity when his trial started in 2020. The jury was not swayed, finding him guilty of murder and attempted murder in March 2020, and Cowell was sentenced to life in prison a few months later.

Cowell’s attorneys appealed the case to the First Appellate District of California, which is a panel of three judges. But the Bay Area News Group reports that Cowell lost his appeal in December, and his convictions and life sentence remain intact.

There is no shortage of evidence that Cowell was an unstable individual. He claimed on the stand that the Wilson sisters were aliens, and had to be removed from the courtroom on multiple occasions over profanity-laden outbursts. But the appeals court was unmoved by this, given that the video evidence still showed an intentional murder, and there was ample evidence that Cowell then tried to cover up his crime and shed the evidence.

“In the 86-page decision, appellate justices ruled that Cowell’s refusal to come to court or obey courtroom decorum didn’t affect his defense,” according to the Bay Area News Group. The panel also wrote that “the evidence that defendant committed the stabbings was overwhelming.”

That evidence was BART surveillance video, which showed that Cowell was tracking the Wilson sisters from the time they entered a BART train at Concord. The news group adds that “Afterwards, he took key steps to get away with the crime, like disposing of the knife, fleeing the area, and changing his clothes, all of which proved he knew he’d done something wrong.”

Under California law, proving insanity is a high bar, as one has to prove that the defendent could not discern between right and wrong at the time of the crime. prosecutors also contended that Cowell intentionally played up his volatility in order to get off.

Cowell will now remain at California State Prison in Sacramento, where he will serve out the remainder of his life sentence, pending any further appeals.

Related: John Lee Cowell Convicted of First-Degree Murder of Nia Wilson [SFist]

Image: (Left) via BART, (Right) Courtesy Nia Wilson family