NORMAN, Okla. — An Oklahoma judge on Friday sentenced a man to death for beheading a co-worker in 2014 at a food processing plant.

Cleveland County District Judge Lori Walkley accepted a jury's recommendation of the death penalty over life in prison without parole for Alton Nolen, 33. Jurors earlier this year convicted him of decapitating 54-year-old Colleen Hufford when he attacked her and others at the Vaughan Foods plant.

During the trial, prosecutors played recordings of Nolen confessing to the stabbings while he was hospitalized following the attack. In the recordings, Nolen says he doesn't "regret it at all" and that "oppressors don't need to be here."

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Investigators said Nolen had just been suspended from his job at the Vaughan Foods plant when he walked inside the company's administrative office and attacked his co-workers.

His attorneys argued that he is mentally ill and that he believed he was doing the right thing because of his delusional misinterpretations of the Quran.

But prosecutors said Nolen knew right from wrong before he attacked Hufford.

Nolen had repeatedly tried to plead guilty and asked to be executed, but Walkley declined to accept his plea. One of Nolen's attorneys had questioned whether his client was mentally competent to enter a guilty plea.