A nurse in Texas has been convicted of capital murder after he was found guilty of killing four patients by injecting them with air following heart surgeries.

The Associated Press reports William Davis, 37, was accused of injecting air into the arteries of four patients at Christus Trinity Mother Frances Hospital in Tyler, Texas, in 2017 and 2018. While recovering from heart surgeries, the four victims, John Lafferty, Ronald Clark, Christopher Greenway and Joseph Kalina, suffered neurological problems and died.

“There is a motive here for Will Davis. It’s simple. He likes to kill people,” prosecutor Chris Gatewood told the Smith County jury. “He enjoyed going into the rooms and injecting them with air. If you watch the video on Kalina, he set at the end of the hall and he watched those monitors and he waited. That’s because he liked it.”

Defense Attorney Phillip Hayes disagreed with the notion that Davis had a motive to kill.

“Will liked to kill people? I don’t know if y’all remember this or if Mr. Gatewood was here for the trial, but at least two of those individuals that passed away Will was trying to administer life-saving drugs to or process to,” Hayes said.

Prosecutors are preparing to seek the death penalty during the sentencing phase, which started last week. Davis remains in custody at the Smith County Jail on an $8.75 million bail bond.