A former Atlanta Police officer said he's been battling Post Traumatic Stress Disorder, undiagnosed, for years.
His lawyers claim that may have contributed to why Matthew Johns kicked and choked an unarmed teenager.
September 15, 2016 changed the lives of Johns and Antraveious Payne forever. 11Alive was the only Atlanta TV station on the ground when a high-speed chase came to an end in southwest Atlanta.
Payne, then 15-years-old, was allegedly riding in a stolen car. But once the vehicle came to a stop, dashcam video shows Payne getting onto the ground.
The video then shows Johns, a Marine Corps veteran, kicking Payne in the head three times. Payne was knocked unconscious.
Johns pleaded guilty to aggravated assault in Fulton County Court Wednesday afternoon. His lawyer asked for Johns to be evaluated to determine if PTSD affected his actions.
Psychologist, Dr. Erik Fisher says that's certainly possible.
"Here you have somebody who is in a pursuit, their adrenaline is running," Fisher explained. "They've had these chronic stress situations that are then gonna affect their ability to process current information."
"This may be an explanation for a behavior. It doesn't excuse his actions. He's pled guilty. He's taken responsibility. Now what we have to look to is the future."
Johns will be evaluated in the next two weeks. He's scheduled to be sentenced on July 29th.
Fulton County District Attorney Paul Howard said regardless of the diagnosis, it shouldn't change the sentencing.
"I just don't think (PTSD) would have a lot to do with this case," Howard said.
The district attorney's office has recommended Johns be sentenced to five years, serving two in prison. Had Johns been convicted, instead of taking a plea deal, he could have faced up to 40 years behind bars.