Tonight at 9: Columbine shooter’s mom breaks her silence in exclusive interview with ABC News.

17 years after the shooting at Columbine High School that killed 13 people, the mother of one of the gunmen is talking publicly for the first time.

Sue Klebold is the mother of Dylan Klebold. She spoke with Diane Sawyer about the tragedy, the victims, her relationship with her son and what it was like inside their home.

Sue and Tom Kelbold have said in the past that they had no idea their son and the second gunman, Eric Harris, were gathering weapons. Nor did they know that their son had been writing about suicide in his journal.

“I had all of those illusions that everything was OK because, and more than anything else, because my love for him was so strong,” Sue Klebold told Sawyer. “I keep thinking, constantly thought, how I would feel if it were the other way around. If one of their children had shot mine. I would feel exactly the way they did. I know I would,” she said.

The Columbine High School shooting redefined how law enforcement responds to school threats.

Susan Payne started Safe2Tell and the program took off after the shooting. Through Safe2Tell, students are able to report tips anonymously online and on their phones. Payne said it provides a forum for students to let people know about threats in a safe environment.

“Just this last semester, we had 105 threats of a planned school attack reported in Colorado. Last year for the entire school year, it was 74. So it gives you an idea that they are a lot more aware,” said Payne.

You’ll hear more from Sue Klebold in the ABC News primetime special “Silence Broken: A Mother’s Reckoning.” The program airs Friday night at 9 p.m. on KRDO NewsChannel 13.