A capital murder trial began Tuesday for a nurse accused of killing four patients at an East Texas hospital in 2017.

William Davis, 37, allegedly killed four men who had been recovering from heart surgery at Christus Trinity Mother Frances Hospital in Tyler by injecting air into their arteries, prosecutors allege.

"No one expects this is going to happen to them — certainly not in a hospital," Smith County District Attorney Jacob Putnam told jurors during opening statements.

"It turns out a hospital is the perfect place for a serial killer to hide," Putnam said.

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The alleged victims were John Lafferty, Ronald Clark, Christopher Greenway and Joseph Kalina. They all died when Davis was the only nurse on duty.

Following their surgery, Putnam said all four patients were in stable condition. But they then suffered stroke-like symptoms, and CT scans showed the men had abnormal arterial spaces in their brains.

Davis’ defense attorney, Phillip Hayes, said his client was simply in the wrong place at the wrong time.

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The lawyer also argued strokes are not uncommon in intensive-care units.

With Post wires