The mother of the alleged gunman wanted for killing one person and injuring at least four others inside an Atlanta hospital says her son opened fire after he received “messed up medication.”

Minyone Patterson – who is cooperating with police as they search for her son, Deion Patterson, 24 – appeared to blame his medication regimen for the shooting at Northside Hospital Medical Midtown Wednesday.

“The damn VA gave him some messed up medication, and all he wanted was an Ativan,” Minyone told The Daily Beast, referring to the medication used to treat seizure disorders such as epilepsy. She did not elaborate further and hung up.

Officials said Deion and his mother were at the hospital on Wednesday afternoon when he became agitated and opened fire.

Minyone’s comment echoes what a source previously told CNN about Deion having a military background.

It is not yet clear exactly what connection Deion has with the military or if he served in any of its branches.

The suspect is currently on the run, and police have warned the public that Patterson may be “armed and dangerous.”

Surveillance photos released showed the shooter wearing dark pants and a gray hoodie with the hood pulled up. He had a mask on their face and appeared to be wearing a satchel across their front.

One of the victims was pronounced dead on the scene, and the others were taken to the nearby Grady Memorial Hospital for treatment, officials said.

Three patients were listed in critical condition, and two were being operated on, Grady Health System Chief Medical Officer Dr. Robert Jansen told reporters.

Several Atlanta schools in the area were locked down “out of an abundance of caution” while the killer remained at large, school officials said.

The order was lifted as police believe the suspect carjacked a vehicle and is out of the downtown area.

Northside Hospital said it was assisting police in their investigation, adding in a statement: “This tragedy is affecting all of us, and we ask for patience and prayers at this time.”

There is currently a $10,000 reward for information leading up to Patterson’s arrest.