TODAY | August 21, 2013
>>> at an elementary school in georgia . parents are asking how a 20-year-old suspect was able to get inside the building with an assault rifle . gabe gutierrez has the story in decatur, georgia . good morning to you.
>> gorod morning. this is not his first rub in with the law. in march he was arrested and charged with making a terroristic threat.
>> reporter: this morning, 20-year-old michael brandon hill is behind bars . investigators spent the night trying to pin down his motive. looking for clues at the rental home he shared with this woman and her boyfriend.
>> he is having a rough time so i just spray for him.
>> reporter: tuesday afternoon hill walked into the front office at ronald mcnair discovery learning academy with an ak-47 and at least one other weapon despite the school security system that required visitors to be buzzed in.
>> we suspect he came in behind someone authorized to be there.
>> reporter: the suspect briefly held at least one employee captive and told her to call a local tv station. as officers approached, investigators say he quickly peaked through the front office door firing at least six shots. police returned fire. by the time three sheriff's deputies and a u.s. marshall entered the building through a u.s. side door the suspect dropped to the ground and surrendered inside the office. no one was injured but it was a frightening ordeal for some students. some evacuated through a hole in the fence.
>> we had to hold hands and they escorted us outside.
>> near the school in a walmart parking lot.
>> this is devastating.
>> reporter: panicked parents waited three hours for their kids.
>> i'm so happy.
>> reporter: one by one, bus by bus, class by class. they were reunited.
>> it was well worth the wait. as long as everybody was safe and everything, it was such a relief.
>> reporter: relief that this time, all the children came home. today this school remains closed. instead, students will attend classes at the nearby high school , savannah.
>>> gabe gutierrez is decatur, georgia . thank you.