The suspect, Alton Nolen, has a lengthy criminal history and a concerning Facebook page.
We're taking a closer look at that and his background.
We know he studied very briefly, a semester, at Langston University and was from Idabel, Oklahoma.
The FBI is investigating Nolen's background including his social media presence.
Investigators are trying to determine if the beheading, the vicious rage, is revenge over a lost job - or something completely different.
Initially it was described as a workplace dispute. But, Moore Police have called in the FBI to assist them on this case.
They may look to social media for clues, and Nolen has left quite the footprint on his Facebook page.
Posted pictures seem to go from one extreme to the other, from the burning twin towers, to Osama Bin Laden.
Several other posts rant about the sins of America in what appears to be a decidedly militant slant.
There's even one, one that is very disturbing, of a beheading. All these were posted within the last six months.
The page clearly reflects Nolen's conversion to Islam, and some of his co-workers tell us he was trying to convince others to join him.
The suspected killer has had his share of run-ins with local authorities, although nothing compared to what happened Thursday evening.
In 2006, Nolen plead guilty to possession of drugs with intent to distribute in Oklahoma City.
In 2009, Langston authorities arrested him for possession, obstructing an officer and escape from detention.
In 2010, he assaulted an OHP Trooper during a traffic stop.
He served about two years in prison, from April 2011 to March 2013.
Right now, authorities have not said if this was a pre-planned act of terror, or if Nolen acted out because of his firing from Vaughn Food's alone.
Of course, the investigation continues.