A man who was shot after he beheaded one woman and attacked another at an Oklahoma food processing plant from which he had just been fired has regained consciousness and has been interviewed by detectives, police said Saturday. Alton Nolen, 30, remains hospitalized in stable condition following Thursday's attack at the Vaughan Foods plant in the Oklahoma City suburb of Moore, Police Sgt. Jeremy Lewis said. He said Nolen will be charged with first-degree murder and assault and battery with a deadly weapon, and that he may also face federal charges.

Lewis said Nolen was fired right before the attack, and that he then drove from the building that houses the company's human resources department to its main distribution center. Once inside, he attacked 54-year-old Colleen Hufford with a knife in the center's administrative office area, eventually severing her head, according to police. Nolen then repeatedly stabbed 43-year-old Traci Johnson before Mark Vaughan, a reserve sheriff's deputy and the company's chief operating officer, shot him.

Johnson survived the attack and is also conscious, Lewis said, adding that she is listed in stable condition. Although the investigation is ongoing, Lewis said police learned Nolen was discharged from Vaughan Foods for "numerous reasons" involving "personnel issues," but that he didn't know the specifics.

Police asked the FBI to help investigate Nolen after co-workers told investigators he had recently started trying to convert several employees to Islam. He said police asked the FBI to look into Lewis' background because of the nature of the attack, which followed a series of high-profile videotaped beheadings by Islamic State militants.