The Georgia mass shooting suspect who was killed Sunday (July 16) by the police after he allegedly shot and killed four people suffered from mental illness, his mother told Atlanta station WSB.

“I feel so much for the families, and that’s why I just want to say I’m very, very sorry. I know words cannot really comfort them from me at this time, but I know there is a comforter, and they can refer to him at any time,” Lorna Dennis said, adding that doctors suspected that he had PTSD and Schizophrenia but never took medication.

NBC News reported that law enforcement identified Andrea Longmore, 40, as the individual who fatally shot four neighbors for an unknown reason on Saturday (July 15) at about 10:45 a.m. in Hampton, located just south of Atlanta. Hampton Police Chief James Turner identified the victims as Scott Levitt, 67; Shirley Levitt, 66; Steve Blizzard, 65; and Ronald Jeffers, 66.

After a manhunt, officials said officers shot and killed Longmore after an exchange of gunfire in which a sheriff’s deputy and two police officers were wounded, the Associated press reported.

“It’s hard to lose your son, and it’s also hard to know your son cost the life of so many people,” Dennis said. She stated that he was a U.S. Army veteran who served as a paratrooper in the 82nd Airborne Division and lived with her in the Hampton community where the shooting happened.

Dennis said her son had a mental breakdown in 2014 and was in a VA hospital for several days. But his condition continued to deteriorate.

“I tried to get some help for him, but they kept saying that he has to commit a crime or, you know, like, break up the house or anything, try to hurt himself,” Dennis said. “But if he wasn’t doing that, he has to come in voluntarily to get medical attention, but he said he doesn’t need it and doesn’t want it.”

The Army said Longmore worked as an automated logistical specialist from August 2000 to May 2006, according to the AP. His job involved overseeing supplies and equipment. He deployed to Afghanistan, served under hostile fire and was a trained parachutist, driver and mechanic.