T.L. Wortham hardly looked like a man about to storm a school where a gunman was threatening the lives of 800 children.

Dressed not in black fatigues and boots, the investigator on the fugitive squad of the DeKalb County Police Department had on shorts and red shoes under his body armor and helmet.

Standing outside Ronald E. McNair Discovery Learning Academy shortly after 1 p.m. Tuesday, Wortham heard shots and saw a man in dark clothing in front of the school.

The man “looked up, saw the officers and shot into the air,” Wortham said. “He wanted us to know he was there.”

They knew all right. DeKalb police, the county Sheriff’s Office, school system police, the GBI, FBI and U.S. Marshals Service — all would eventually gather at the elementary school fearful that the scourge of school massacres had arrived in metro Atlanta.

That it didn’t, and that Michael Brandon Hill surrendered peacefully with not a single injury to anyone, emerged as a testament to the planning and execution of law enforcement and the remarkable composure of a school employee who facilitated the surrender.

But, before that peaceful ending, Wortham and other officers had to prepare for the worst and to accept whatever came. They said nothing once they were in position because with years of training together they already knew what each man would do. Investigator J. Hunt, assigned to a joint federal-local fugitive task force, briefed six officers from the U.S. Marshals Service. A school resource officer produced a key card to open a side door to the school.

“Decisions were made instantly,” Hunt said.

School bookkeeper Antoinette Tuff was inside with the gunman. Two calls to 911 over 24 minutes capture her words to the gunman, identified on the call as Hill, as well as what she told the operator, sometimes in relaying messages from the gunman. Gunfire also can be heard.

“Tell them to back off!” Tuff tells the operator. “Do not let anybody in the building. Including no police.”

Shots are heard as Tuff says the man went outside and started shooting. The operator, calm throughout, tells Tuff not to hang up the phone, but to lay it down on the counter so she can hear.

Later, Tuff says the shooter says he doesn’t care if he dies. He admits mental problems. Tuff tells him it’s OK. Tuff offers to escort the man outside to surrender and asks the operator for permission.

Tuff pleads with the gunman, consoles him.

“I’m sitting here with you and talking to you about it,” Tuff says.

Tuff tells him that her husband left her after 33 years, that she considered suicide and has a disabled child.

The gunman eventually agrees to give Tuff his weapons and to lie down on the floor, hands behind his back, and gives police permission to enter the school.

“We’re not going to hate you, baby,” Tuff says.

“It’s going to be all right, sweetie. I want you to know I love you, though, and I’m proud of you. We all go through something in life.”

At that point, 10 officers creep down the hall to the edge of the office. Doors are closed and students are in the classrooms.

There is no sound. (“You would have thought the school was empty,” Hunt said later.)

Wortham peeks around the corner and sees Hill lying face down on the floor. A rifle is on the counter, and Tuff stands at the desk.

Hill is taken into custody and Tuff finally exhales.

“I’ll tell you something, baby, I’ve never been so scared any day of my life,” Tuff tells the 911 operator. “Oh, Jesus. Oh, God.”

This incident had a familiar ring, said Ken Trump, a national school safety expert. “It’s largely become the same plot, but with a different cast of characters. There’s also one very common thread: people with mental health issues,” Trump said.

“Had (Tuff) thrown a stapler,” he said, “you would have had a much worse outcome.

“I think certainly what was done was the right response — the way she remained calm. She didn’t freeze. She didn’t go off. She didn’t do anything extreme. She made the right decisions that saved her own life and possibly others.”

When police first arrived they had no way of knowing whether the shooter inside had designs on killing himself or others or was simply a mentally ill young man in search of attention.

And it made no difference.

DeKalb Police Chief Cedric Alexander said Wednesday that they had only one choice: Prepare for the worst, execute their plan and stop the bad man with the gun. In the end, they did and remarkably no one was injured. The police response to the incident has been hailed for its effectiveness and efficiency.

The gunman “walked into a school of his own volition, as far as we know, with an automatic assault weapon and 498 rounds [of ammunition],” Alexander said during a news conference Wednesday. “He was there to harm somebody, and we have to respond accordingly.”

While the skill of those involved surely played a role, there was also a good bit of luck on the law enforcement side. A GBI special agent was nearby accompanying a DeKalb officer investigating a child exploitation case, GBI Special Agent Sherry Lang said. Two GBI command staff agents happened to be having lunch at the same restaurant as some county detectives when the call came in.

In these types of situations, Lang said, “it is just so chaotic because everyone is going in every direction and law enforcement is trying to assess what’s going on.”

Eric Wojtkun, a crisis management coordinator for the FBI’s Atlanta office, said FBI special agents were there to provide help if needed. He said the FBI had units on the scene within 25 to 30 minutes after the incident began.

“We were there as consultants in case we needed to open the floodgates,” Wojtkun said. “DeKalb had all the resources necessary, both tactically and investigatively.”

He said police had the situation in hand before the FBI arrived.

Said Wojtkun: “When we rolled up there, it was seamless.”