Francisco Severo Torres, 33, of Leominster, was charged in March with interference and attempted interference with flight crew members and attendants using a dangerous weapon, which could carry a life sentence in prison, the US Attorney for Massachusetts said.
Magistrate Judge Judith Dein wrote in her ruling that Torres was not competent enough to assist in his defense or understand the trial's consequences, according to the Associated Press.
"The Court hereby finds … that the defendant is presently suffering from a mental disease or defect rendering him mentally incompetent to the extent that he is unable to understand the nature and consequences of the proceedings against him or to assist properly in his defense."
Torres remains in federal custody.
'There's Going To Be A Bloodbath'
Video taken on the United Airlines flight shows a deranged Torres screaming at passengers that he was one of the three kings who greeted Jesus at his birth. He promised to kill everyone in a "blood bath" when the plane landed but would offer mercy to those who begged for their lives.
"If you're men, you can run, and I won't kill you," Torres screams in the video. "I'm Balthazar. You just put up your hands and say, 'Don't kill me.' That works. Don't approach me because I'm Balthazar."
Torres threatened to take over the plane, charged flight attendants with a metal spoon, and tried to open the door. Several passengers tackled him and pinned him to the ground until they landed.
United Airlines banned him from any future flights.
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