Updated: January 23, 2014

A 20-year-old man who went to a Georgia elementary school with an AK-47 assault rifle and close to 500 rounds ammunition told a school clerk that he was prepared to die in the attack. But the woman calmly persuaded him to lay down his weapon.

According to 911 tapes released Wednesday, Michael Brandon Hill said he didn’t care about dying and should have just gone to a mental hospital.

Hill followed someone into Ronald E. McNair Discovery Learning Academy filled with 800 schoolchildren just outside Atlanta, and made his way to the elementary school’s front desk, demanding that someone call a local television station. Antoinette Tuff, a school bookkeeper, called 911 and stayed on the line for nearly 25 minutes.

Tuff told the 911 operator that Hill said he “should have just went to the mental hospital instead of doing this because he is not on his medication.”

“He said he don’t care if he dies, he don’t have nothing to live for,” Tuff told the operator. “He said he’s not mentally stable.”

Close video How Antoinette Tuff stopped armed intruder Antoinette Tuff, the heroic bookkeeper who saved an entire elementary school by convincing an armed intruder to surrender, joins Lawrence O’Donnell to discuss her new book. Antoinette Tuff, the heroic bookkeeper who saved an entire elementary school by convincing an armed intruder to surrender, joins Lawrence O’Donnell to discuss her new book. share tweet email Embed

After police arrived on the scene, the gunman stepped outside and fired multiple shots and went back inside the main office. Once he returned, Tuff talked Hill into surrendering. and their 20-minute exchange was caught on tape. “I just started telling him my life story and what was going on with me,” Tuff said in an interview with ABC News.

“That’s a good thing that you just giving up, and don’t worry about it. We all go through something in life,” she can be heard telling Hill.

“Don’t feel bad, baby,” she told the young man. “My husband just left me after 33 years… I’ve got a son that’s multiple disabled.”

Once Hill listened to Tuff, she told the operator, “OK, he said that they can come in now. He needs to go to the hospital.” Hill emptied his pockets, set down his backpack and put his weapons down. When police officers came inside, Hill was lying on the floor with his hands behind his back.

In an interview with WSBTV News, Tuff revealed how afraid she actually was. “I’m not the hero, I was terrified,” she said.

“He actually tried to go out the door where the kids were and I called him back and kept talking to him to keep him calm, to stay inside with me…because I knew that if he got outside he was going to start shooting kids. It was scary because I knew that at that moment he was ready to take my life along with his, and if I didn’t say the right thing we would all be dead,” Tuff said.

DeKalb County Police Detective Ray Davis, the lead investigator on the case, said Wednesday that authorities are working on locating the owner of the rifle Hill carried. Davis said leads show that Hill took the gun from an acquaintance’s house.

Hill’s public defender disclosed on Wednesday that Hill has a long history of mental health issues, which Tuff also mentioned to DeKalb County emergency dispatchers. Hill told Tuff that he was on probation and undergoing anger counseling after making threats to shoot his brother, Timothy Hill, who confirmed the charge to NBC News. In July, Hill pled guilty to the charge, which would have not allowed him to legally purchase or possess a weapon.

“He had to get them from buying them off the streets,” Timothy Hill told NBC News. “There is no way possible a gun store would sell them to him with his mental history. And no gun laws would have prevented that.”

Hill is charged with aggravated assault on a police officer, making terroristic threats and possession of a firearm by a convicted felon.