The brother of the 20-year-old man who police say went to an Atlanta-area school heavily armed and exchanged gunfire with officers before surrendering says he was a normal kid growing up, but began to change as a teenager and engage in threatening behavior.
Tim Hill told CNN's Piers Morgan that Michael Brandon Hill began acting erratically after doctors adjusted his medications and he was institutionalized on several occasions.
The older brother's comments came two days after a school bookkeeper helped persuade Michael Hill to surrender to police following a frightening standoff and shooting Tuesday at Ronald E. McNair Discovery Learning Academy in Decatur, an Atlanta suburb.
No one was hurt, though police say Hill went to the school armed with an AK 47-style rifle and nearly 500 rounds of ammunition.
DeKalb County School officials say U.S. Secretary of Education Arne Duncan is planning a video conference with district officials to discuss the shooting.
Officials say Duncan plans to speak with Interim Superintendent Michael Thurmond and other district representatives Friday morning about how the district responded.
The school was evacuated during the standoff. Hill has been arrested on several criminal charges.
Meanwhile, President Barack Obama has phoned the bookkeeper credited with helping prevent more violence to thank her for her actions.
The White House says Obama spoke with Antoinette Tuff on Thursday while in New York, where he is on an education-focused bus trip.
Police say Tuff, a school bookkeeper, was heroic in how she responded after being taken hostage by the gunman. They credit her calm demeanor and kind approach with persuading the man to surrender and ending the ordeal without any injuries.