Prison records indicate that the man suspected of beheading a co-worker at an Oklahoma food processing plant had spent time in prison and was on probation for assaulting a police officer.

Police say 30-year-old Alton Nolen is accused of stabbing two women Thursday at Vaughan Foods in Moore, an Oklahoma City suburb. One woman was killed, her head severed. The other is hospitalized.

'It could have gotten a lot worse.' - Moore Police Sgt. Jeremy Lewis

Nolen, who was fired from the food processing plant, had beheaded a woman with a knife and was attacking another worker when he was shot and wounded by a company official, police said Friday.

Moore Police Sgt. Jeremy Lewis said police are waiting until Nolen is conscious to arrest him in Thursday's attack and have asked the FBI to help investigate after co-workers told authorities that he recently started trying to convert several employees to Islam.

Nolen allegedly stabbed Colleen Hufford, 54, severing her head, Lewis said.

"Yes, she was beheaded," Lewis told The Associated Press before a Friday news conference.

Suspect has 'peace be with you' tattoo

Lewis said Nolen then allegedly stabbed Traci Johnson, 43, a number of times before Mark Vaughan, a reserve sheriff's deputy and the company's chief operating officer, shot him.

"This was not going to stop if he didn't stop it. It could have gotten a lot worse," Lewis said. "The threat had already stopped once we arrived."

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The FBI has been asked to investigate the background of the suspect, 30-year-old Alton Alexander Nolen. (Oklahoma Department of Corrections/Reuters)

Lewis said Moore police have asked the FBI to look into the man's background because of the nature of the attack, which follows a series of videotaped beheadings by ISIS militants.

In a statement, FBI Special Agent in Charge James E. Finch said the motive for the attack has not been determined but that there is no reason to believe there is a threat to anyone else.

Johnson and the suspect were hospitalized and in stable condition Friday, Lewis said. He did not yet know what charges will be filed.

Oklahoma Department of Corrections records indicate Nolen has served time in prison and is on probation for assault and battery on a police officer. He also was convicted of cocaine possession with intent to distribute in 2011.

Corrections records show Nolen has multiple, apparently religious tattoos, including one referencing Jesus and one in Arabic that means "peace be with you."

Lewis said Nolen had been fired in a building that houses the company's human resources office, then immediately drove to the entrance of the business. Lewis said he didn't know why the man was fired.

A Vaughan spokeswoman said the company was "shocked and deeply saddened" by the attack.