Last Updated Sep 30, 2014 1:28 PM EDT
NORMAN, Okla. - An Oklahoma man was charged Tuesday with first-degree murder in the gruesome beheading of a Vaughan Foods worker, authorities said.
Cleveland County prosecutor Greg Mashburn said 30-year-old Alton Nolen faces murder and assault charges. The attack killed 54-year-old Colleen Hufford, and 43-year-old Traci Johnson was repeatedly stabbed, although she survived.
Nolen had been fired from the company just before he walked into the plant's administrative office in suburban Oklahoma City on Thursday and allegedly attacked the women. The company's chief operating officer, who is also a reserve sheriff's deputy, shot Nolen, stopping the attack, police said.
Nolen's family says he recently had converted to Islam and authorities have said they obtained information that Nolen had been trying to convince co-workers to also convert to Islam. Mashburn said Tuesday federal authorities were still investigating whether there was any connection between Nolen's religious beliefs and the attack.
In a letter obtained by CBS News Thursday, Congressman Frank Wolf (R-Va.) asks Attorney General Eric Holder and the Justice Department to not dismiss the incident as "workplace violence" and to treat it as an act of terrorism.
The letter references the 2009 attack on Fort Hood, which left 13 dead and more than 30 wounded. Wolf cites that as an example of an incident that should have been recognized as an act of terrorism but initially was not.
"In the wake of the department's failure to 'connect the dots' between [Muslim cleric] Anwar Aulaqi and Fort Hood terrorist Nidal Hassan, it is more important than ever for you to make clear to the department's agents and attorneys that this is, in fact, terrorism and to determine whether this or other plots are part of an effort by the Islamic State of Iraq and Syria (ISIS) or al Qaeda to radicalize Americans and direct attacks in the U.S.," Wolf wrote.
Nolen's mother and sister posted a video message on Facebook over the weekend saying they were shocked and saddened by the allegations against him.
"My son was raised up in a loving home. My son was raised up believing in God," his mother, Joyce Nolen, said in the video. "Our hearts bleed right now because of what they're saying Alton has done."
A cousin, 29-year-old James Fulsom, told The Associated Press that as recently as February, Nolen did not mention his conversion in conversations.
Oklahoma prison records show Nolen was released from prison in March 2013 after serving two years of a six-year sentence on charges that included assaulting a police officer and possession of cocaine with intent to distribute.
Nolen received no misconduct reports during his incarceration at five separate facilities, Department of Corrections spokesman Jerry Massie said. Nolen completed his probation in March of this year.