Columbine shooter’s mother breaks her silence for first time in 17 years

Sue Klebold said her mistake was not realising the importance of what seemed to be an 'adolescence phase' in her son's behaviour

Sue Klebold said she didn't realise her son was living in a 'completely different world' (ABC News)

The mother of Columbine high school shooter Dylan Klebold has spoken publicly for the first time in 17 years about one of the most notorious high school massacres in American history.

Sue Klebold has written a book called “Silence Broken: A Mother’s Reckoning”, and all proceeds will go to mental health charities.

Speaking to ABC news anchor Diane Sawyer, she said she got a call from her husband at the office on 20 April 1999 to say there had been an emergency at the high school and police suspected one of the killers was her 18-year-old son.

Dylan Klebold and Eric Harris carried out a highly sophisticated attack, using a fire bomb to divert emergency services. They murdered 13 people and injured a further 21 before committing suicide.

Ms Klebold said she had seen something bothering her son but “wrote it off as adolescent depression”.

“Part of the shock of this was learning that what I believed, and how I lived and how I parented, was an invention in my own mind - that it was a completely different world he [Dylan] was living in,” she said.

She warned that little behavioural signs could indicate “something profound”.

“It’s very hard to live with the fact that someone you loved and raised has brutally killed people in such a horrific way,” she said.

“I think we like to believe that our love and our understanding is protective and that if anything is wrong with our kids, I would know,” she said. “But I didn’t know. And it’s very hard to live with that.”

She added that she thinks of the victims - 12 teenagers and a teacher - and their families every day.

The interview is being aired on ABC news on the same day as a suspected shooting in Arizona.

Interviewer Ms Sawyers reported there have been over 70 “thwarted” high school shootings since Columbine.

Ms Sawyer told her colleagues that for Ms Kebold, “a moment of happiness is a moment without suffering."

Some families allegedly carry “immense anger” towards her and have blamed Ms Klebold for not coming forward sooner, while others have forgiven her and her son, said Ms Sawyer.

One victim, Anne Marie Hochhalter, who was left paralyzed by the attack, penned a letter to Ms Klebold and her husband Tom, saying she forgave them and was touched that the book proceeds will go to charity.

“It's been a rough road for me, with many medical issues because of my spinal cord injury and intense nerve pain, but I choose not to be bitter towards you. A good friend once told me, ”Bitterness is like swallowing a poison pill and expecting the other person to die.“ It only harms yourself. I have forgiven you and only wish you the best,” she wrote on her Facebook page.