NORMAN, Okla. -- Officials say 12 jurors and three alternates have been seated in the trial of beheading suspect Alton Nolen.
Nolen stands accused of beheading a former coworker and stabbing another in September 2014. Authorities say Nolen stabbed 54-year-old Colleen Hufford multiple times and beheaded her inside the Vaughan Foods distribution center on September 25, 2014.
After attacking Hufford, Nolen allegedly stabbed 43-year-old Traci Johnson numerous times before he was shot by Mark Vaughan, the former CEO of the company and a reserve sheriff's deputy.
Hufford died from her injuries, but Johnson survived.
In court Thursday, Nolen sat in court surrounded by two sheriff's deputies. His eyes were shut, and his ears were covered.
During opening statements, Cleveland County District Attorney Greg Mashburn argued Nolen "brutally" murdered Hufford after he went home to grab a knife after an apparent altercation at Vaughn Foods that day.
According to Mashburn, who went into graphic detail, it was well know that security guards left at 4 p.m. each day.
The defense argues that it is clear that Nolen killed Hufford, but says Nolen is mentally ill and did not understand what he was doing was wrong.
Before being selected, the jurors were questioned on their educational background and family history of mental illnesses.
They were also asked if they would be able to stay impartial to Nolen's behavior in court and whether they had a chance to review all three possible sentencing options should Nolen be found guilty, which includes the death penalty.
Trial resumes on Friday.