Columbine anniversary: ​​Senior Principal Frank DeAngelis is still learning how to move on

At first, he was bound to stay at the helm until every student who'd been at school that unimaginable morning had graduated. Then, he has grown up, who has been in that class, down to preschoolers, had earned a diploma.

Since stepping away from the principal office, he has continued his commitment to collective recovery – and expanded his flock beyond Columbine High School.

Five years after retiring, the 64-year-old is as busy as ever, to the principals and communities that have fallen victim to the scourge of school shoots. It's the latest version of an evolving role, however unwelcome, he has pioneered since April 20, 1999.

"Columbine offers hope," Frank told CNN. "And that's what I hope, 20 years later, that we're doing, that we're reaching out to other people – the Parklands, the Santa Fes, the Sandy Hooks, the Virginia Techs."

"I feel I was chosen to do that."

"It always comes to a head right before the anniversary," she said. "And I just hope that with the 20th, that this is the last anniversary that is so big that we can move on a bit."

A devoted educator faces the unthinkable

When Frank was 13, he got a job in a pizzeria. In high school, he delivered newspapers. Frank's parents taught hard work and dedication, and when he got sick, he hardly ever missed work.

Diane, who dated Frank in high school, said he was nice but very serious. He did not have a sense of humor. The couple spent their time together, and while still in high school, Frank gave him a ring and said he wanted to get married. Diane did not want that, she said, so they broke up.

"I had no spontaneity … I was so serious," Frank admitted. "I was 15 or 16 going on 30, and I had to plan my whole life out."

Even so, Frank was unsure what he wanted to study in college, his brother said. But they had both played sports growing up, so when Frank told his brother he'd become an educator, Anthony DeAngelis assumed it was for the sake of athletics.

"I thought, 'He's probably going to be pretty good at this,'" Anthony said.

As with all things, Frank dove in deep. Early in his career, Frank's main ounce forced him to fork over his keys to the school for a weekend. "He said, 'I do not want to see you around this school, Frank, you need to get away,'" he remembered.

Frank displayed that same commitment to each of his students and the baseball players he coached, said Tom Tonelli, one of Frank's educate pupils and a Columbine High School graduate who went on to teach at the school.

"It was always a good student," said Tonelli of Frank's expectations.

Still today when Frank's brother hands over his credit card at restaurants, servers often ask if he's related to Frank, Anthony said. A waitress last year told him Frank had been her principal.

"And she goes on, 'You could talk to any of my friends.

That feeling, who was on staff at Columbine's day gunfire erupted.

"Do I think the shooting?" Absolutely, "the teacher said. "But to say somehow he has become a totally different type of person, I do not think so." The character he exhibited in the wake of the tragedy is just a reflection of who he was before it happened.

When 'the world did not believe in us,' he did

Columbine High School serves middle-and upper-middle-class communities in Littleton, Colorado, where the mountains in the west rise into a wide open sky. Before the massacre, it was an "ideal" community, Frank said, with a lot of parental support and where he "could count on my two hands the number of fistfights we had in 20 years."

After the shooting, Frank "felt this enormous burden to go to rebuild that community," he said. That's when he made the promise to stay at Columbine until the Class of 2002 had graduated. Other staff members made the same commitment, he said.

But in 2001, Frank felt he had not accomplished what he'd set out to do.

"There were so many people deeply impacted, even the kids in elementary school," he said. "So, I made a promise that I would like to be graduated, which would be 2012."

Two years after that, he finally left.

Frank's promised to stay crowned "so much credibility in the community," Tonelli said. The faculty and staff, along with the students and the whole community, looked to him as a leader, as someone who was "persevering for a cause greater than himself."

The perception stuck, even in the face of criticism that the school's administrators and faculty had fostered a student culture "where something like this could happen," said Tonelli, referring to the shooting claim "unjust."

The notion that there were certain segments of the population we did not care about was untrue, "the teacher said.

Through it all, Frank's "leadership meant everything," he said. "He was the biggest believer in our kids and we loved them in our community when we felt like the rest of the world did not believe in us anymore."

A leading battles darkness at home

But as he worked to help Columbine recover, Frank was also an ordinary survivor. At home, his heroic veneer vanished, giving way to the reality of post-traumatic stress disorder.

"I tried to do everything to protect what I call the Columbine family," Frank recalled. "But when I would come home, I just wanted to be left alone."

He did not want to talk with his first wife and two stepchildren about what happened; they just did not understand the aftermath, he said.

"It costs me my marriage," he said. "My wife was saying, 'You're not the same person I married you've changed.' And I did, I felt so much guilt. "

His trauma manifested in other ways, too. Months after the shooting, Frank and his brother went to a Colorado Rockies game. When fireworks reads up the sky, Anthony said, "My brother almost took cover." Later, Frank told Anthony the celebratory poster took him back to the attack.

More shell shock set in when Frank returned to Columbine the summer after the shooting to prepare for the new academic year. Bangs and rumbles echoed as construction crews repaired damage to the building.

"I would have to go back to my office," he said, "and I would cry."

Hope thrives in 'tough love'

Ahead of the Massacre's Third Anniversary, "The Story of the Dead", "Frank began pecking away at the mountain of unopened letters. Among the first he was picked up from his high school sweetheart, Diane.

They started talking regularly, but late in the night, but agreed not to see each other until Frank's marriage was dissolved.

"There was still a spark," said Diane, and she could tell Frank had grown up. "I could see that he had a sense of humor," she laughed, but also that his core features had not changed. "Some of the good things that brought us together were there from the beginning."

But their relationship developed, Frank continued to wrestle with his trauma. As with many Columbine Survivors, it's gotten into the advent of April, a month in which Frank has gotten into six because he's wrecks and when he's always paying attention to the terror.

He leaned on counseling and his Catholic faith, but he was living alone in a vacant house, with only a few pictures and a single bed left after everything else was sold off.

"Twenty years of my life was in shambles," he said. "I was struggling," and he eventually started to drink.

Diane, whose father was a recovered alcoholic, quickly caught on. Frank started hanging up the phone around in the afternoon, she said, and telling her they would talk the next day.

"Immediately, I knew," she said. "I thought, I do not know if I'm going to have this, because I can not go down that path again."

Diane's father died that April; Frank attended the visitation, and they began seeing each other. Soon, Diane caught him drinking. "I can not do this," she told him.

"It was justifiable," Frank said, looking back. "That was what I needed, that tough love … I was so fortunate she came back into my life, and I did not want to do anything to do it."

Leading the 'Nobody Wanted to Join'

When he talks to people who have lived through school shoots, Frank mentions the risk of using alcohol or drugs to cope, and he emphasizes the importance of finding positive sources of support.

It's just one of many pieces of advice in his book, "A Club Nobody Wanted to Join."

Columbine was not the first school shooting, and it was not last. But each time another mass murder happens at a school, Frank said, his phone calls for help.

"Not that I'm an expert," he said, "but I lived through it."

Andy Fetchik, the senior trainer of Chardon High School in Ohio, where three students were killed in a shooting in February 2012.

The first thing Frank said was, "We are now members of the same fraternity that one of us pledged," Fetchik told CNN. "And the second thing he asked me to do to write down his cell phone number."

Next day, he gave Frank a call, he said.

"There was a peace of mind in that person," Fetchik said, noting that he was able to take the steps he had taken to help his Ohio school community heal.

Several years later, Frank visited Chardon High School to talk with faculty members about the recovery process.

"One of the things I struggled with in the recovery of the needs of the staff." We did not always know what they needed, "Fetchik said. "Frank was that voice of somebody who was there, who said, 'Where are you going?'"

'Columbine is not going to define me'

It falls in line with the work Frank has committed since he retired. Last year, he gave about 50 presentations in the United States and Canada about the recovery process. He also said, he said, knowing his name and connection to Columbine carry weight.

But he's tired, Diane said, and she's made it clear she hopes for the future of the 20th anniversary of the event.

"He's doing a lot of good out there," she told CNN. "But I worry about his health, because it has not been great.

For a man who's been working since he was a kid, "I can not imagine myself being completely retired," Frank said. And he knows he'll always want to help suffering communities. But he admits he needs to lighten his load.

"I'm looking at the 20-year remembrance, I need to reevaluate," he said. "I need to give myself permission."

When he retired, Frank said, Diana told him she would not be pregnant with Columbine. Around that time, he started worrying about his own health and suffering with anxiety. But the doctor told him he was fine.

Then, he visited another expert who pinpointed the problem. "You have been a part of Columbine for 35 years," Frank's therapist told him, he recalled. "And you feel that Columbine is Frank DeAngelis. "

That perspective set the stage for a new outlook, Frank said. It's one of those things he wants to embrace, though

"He made me realize that Columbine is not going to define me and that helped a lot," the principal said. "I just got to get it in my mind that it's OK."