First-degree murder charges were filed against Moore, OK beheading suspect Alton Alexander Nolen on Wednesday - and prosecutors say that it is likely he'll face the death penalty. 

"I have a murder charge, that we will vigorously prosecute, and two other charges that carry up to life in prison," District Attorney George Mashburn told a press conference Wednesday.

"It is highly likely that I will seek the death penalty in this case," Mashburn added, noting that he will consult with the family of victim Colleen Hufford, 54. 

The FBI has also gotten involved in the case, Mashburn revealed - confirming reports that Nolen shouted Arabic or Islamic phrases during the rampage.

The FBI is apparently still convinced, however, that there is no link between the attack and terrorism. 

"My understanding is that the altercation that occurred earlier in the day had more to do with race, than it was him trying to convert anyone," Mashburn said, referring to Nolen's losing his job hours before the attack at the same location. "He was basically saying he didn't like white people and had an altercation with our second victim [Traci Johnson, 43] regarding that." 

Early reports indicated that Nolen, 30, had been trying to convert his co-workers at the Vaughan Food processing plant in Moore, OK to Islam shortly before the rampage - and had been fired for it.

Nolen was later revealed to have a detailed criminal record and a proclivity for posting violent and Islamist messages on social media. There, he called himself Jah’Keem Yisrael - a name he adopted after converting to Islam while in prison over drug and assault charges.

Despite this, FBI agents have still yet to call the incident a terror attack, a law enforcement official told the New York Times on condition of anonymity. 

“It’s a mixed bag so far. Beyond being fired, we haven’t found another motive,” the official noted. 

The FBI have so far scoured Nolen's social media posts - many of them on Al Qaeda and ISIS - and searched his electronic devices for more evidence.