The Ector County District Attorney's Office tells Big 2 Trevor Terrell Atchison will now be sent to the North Texas Mental Hospital in Vernon for up to 120 days for treatment.
Once Atchison's treatment at the facility is complete, he will be re-evaluated to see if he can stand trial.
Atchison is charged with murder and two counts of aggravated robbery for his alleged role in an alleged robbery gone wrong.
Investigators say Atchison, 18, tried to rob Evan Fitts in a moving pickup truck that was driving along North Dixie Avenue near Sherwood Park on November 11, 2011. Two other people were also in the vehicle at the time.
At some point during the incident, someone shot Fitts, 19, in the back. The truck eventually crashed into a house on East 49th Street.
Fitts and several others jumped out of the truck before it crashed. Fitts was rushed to Medical Center Hospital, where he was pronounced dead.
Atchison was indicted on January 27th.
A second suspect in the shooting has yet to be indicted.
In addition to the shooting, Odessa Police say Atchison also stole a woman's purse at gunpoint at an alley in the 300 block on East 48th Street on November 8th.
The incidents reportedly happened while Atchison was wearing an ankle monitor for probation. The monitor showed that Atchison was away from his home at the time of the fatal shooting of Fitts.
Atchison was also accused of another robbery in the Permian High School parking lot in December 2010.