Columbine High School Principal: 'I Am Part of a Club No One Wants to Belong To'

Frank DeAngelis risked his life to save students 20 years ago.

When two gunmen opened fire at Columbine High School 20 years ago, Principal Frank DeAngelis didn't hesitate.

"I saw the gunman but I also saw my kids," he told Inside Edition. "People ask me, 'Frank, why did you run towards the gunman?' and I say, 'Because I had to save my kids.'"

DeAngelis took about 20 students to safety and was not himself injured. But 12 of his students were killed, as well as one teacher, and at least 20 other people were injured. The two gunmen, who had also planted bombs at the school, took their own lives after the shooting.

April 20 marks 20 years since the tragedy

"I am apart of a club that no one wants to belong to," he said.

DeAngelis hopes sharing his story will inspire others in need of healing. He has written a book, "They Call Me 'Mr. De': The Story of Columbine's Heart, Resilience and Recovery." All proceeds go to charity.

"Columbine represents hope for others in similar situations," he said.

Mr. De retired in 2013, once all the students who had been enrolled in the school system during the shooting had graduated. On his desk, he kept photos of the 13 people who lost their lives.

"Each morning, I recited the names of those we had lost. As long as I'm alive, I will continue sharing their names and telling their stories," he said.

Click here to read an excerpt from "They Call Me 'Mr. De.'"