School Shooting Suspect Had 500 Rounds Michael Brandon Hill previously threatened to kill brother By John Johnson, Newser Staff Posted Aug 21, 2013 4:29 PM CDT 81 comments Comments Michael Brandon Hill, in a photo released by the Dekalb County Sheriff's Department. (AP Photo/Dekalb County Sheriff's Department) (Newser) – It could have been a disaster: Police say the 20-year-old arrested at an Atlanta-area school yesterday with an AK-47 had 500 rounds of ammunition with him, reports WSB-TV. Though Michael Brandon Hill fired a few shots at police, nobody was injured before his arrest in a school office. It also appears that Hill has a history of mental illness. CBS News reports that police arrested him earlier this year after he threatened on Facebook to shoot his brother in the head "and not think twice about it." His brother told police that Hill had "mental issues" and was seeing a doctor. One investigator on the scene of yesterday's arrest said Hill apologized to officers, saying, "I'm sorry, I'm off my meds," reports USA Today. And the school clerk credited with keeping Hill talking instead of shooting says he told her he had nothing to live for and seemed bent on being killed in a shootout with police. The AP talks to a woman whose family took in Hill while he was in his late teens, and she, too, said he was mentally ill, though she didn't know him to be violent. "This is not the Mike that I know." She said Hill told her that his mother was dead and that he didn't know his father.