A 20-year-old man who fired an AK-47 in a suburban Atlanta elementary school has a history of mental illness and once threatened in a Facebook message to kill his brother, according to the suspect's lawyer and family.
A school clerk convinced Michael Brandon Hill to lay down his gun and turn himself in after he walked into the school carrying 500 rounds of ammunition and briefly exchanged gunfire with police. No students were injured in the incident.
Claudia Saari, a public defender, described Hill as having a "long" history of mental health issues. "Mr. Hill is being represented by members of our Mental Health Division," she said.
The shooting was the latest involving a gunman suffering from a mental health problem, an issue that has raised questions over whether background checks go far enough in examining potential gun buyers.
A spate of shootings at U.S. schools has also reignited a public debate about how to improve safety, with some gun rights advocates calling for more armed security guards and training for teachers to carry weapons.
The Atlanta incident came less than a year after a heavily armed gunman opened fire at Sandy Hook Elementary School in Newtown, Connecticut, killing 20 children and six adults.
Timothy Hill, the brother of the Atlanta gunman, told police he received threatening messages on Facebook from his brother, including one that stated he would "shoot him in the head and not think twice about it," a December 2012 police report said.
Timothy Hill said at the time "he was in fear for his life" and wanted to pursue charges against his brother, the report said. He told officers his brother was under a doctor's care because of his mental issues, according to the report.
Michael Hill was sentenced in July to three years probation and ordered to attend anger management classes for the threat made against his brother, according to Henry County Court records.
Police in the Atlanta suburb of Decatur and school officials praised Antoinette Tuff, a school clerk at the Ronald E. McNair Discovery Learning Academy, with preventing a potential tragedy by persuading Hill to put his weapon down and end the ordeal.
"She was just smart enough, brave enough, compassionate enough to stop him," Michael Thurmond, interim superintendent of the DeKalb County school system, told CNN.
In a recording of a 911 call released by police, Tuff can be heard calmly talking Hill out of causing harm and reassuring him that giving up was the right thing to do.
"It's going to be all right sweetheart," she told Hill as he discarded his weapon, emptied his pockets and waited for police to enter the school.
Tuff, who was relaying messages from Hill to police, spoke at length with Hill, telling him "we all go through something in life" and explaining how she tried to commit suicide after her husband of 33 years left her last year.
At the end, Hill lay face down on the floor so police could come in and arrest him.
Tuff can be heard on the 911 call telling the police dispatcher, "I'll buzz them in. Tell them not to come in shooting."
Authorities are trying to piece together how Hill obtained his gun.
Regina Milledge, a spokeswoman for the federal Bureau of Alcohol, Tobacco and Firearms and Explosives told Reuters on Thursday the AK-47 was purchased by an individual from a federally licensed gun dealer.
She declined to say who purchased the weapon.
Students at the school returned to the building on Thursday for the first time after the shooting, said Quinn Hudson, a DeKalb County school system spokesman.
Crisis counselors were on hand to talk with students, he said.
Students who spoke with counselors were not afraid but wanted "reassurance that everything is OK," Hudson said.