The mother of Columbine shooter Dylan Klebold gives her first-ever TV interview tonight on Diane Sawyer’s prime-time ABC show 20/20.

The broadcast comes ahead of the publication of Sue Klebold’s book, Silence Broken: A Mother’s Reckoning.

In Friday’s special edition of the show, which will air at 9pm on KMGH-Channel 7, Mrs Klebold talks about her relationship with her son, what it was like in their home in the days leading up to the massacre at Columbine High School and her thoughts on the victims.

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The mother of Columbine shooter Dylan Klebold gives her first-ever TV interview tonight on Diane Sawyer’s prime-time ABC show 20/20

Diane Sawyer's interview comes ahead of the publication of Sue Klebold’s book, Silence Broken: A Mother’s Reckoning

In Friday’s special edition of the show, which will air at 9pm on KMGH-Channel 7, Mrs Klebold talks about her relationship with her son

Klebold has said that the Sandy Hook shootings of 2012 helped convince her to share her story

In 1999, Dylan Klebold (right) and fellow senior student Eric Harris killed 12 students and one teacher at the Colorado high school before taking their own lives

Pre-meditated: Dylan Klebol's (pictured) large-scale attack also involved a fire bomb used to distract fire fighters

At one point in the interview Sawyer asks Mrs Klebod: ‘For all the parents who said “I would have known something…”'

She replies: ‘Before Columbine happened, I would have been one of those parents.

‘I had all the illusions that everything was ok. My love for him was so strong.’

When speaking about the victims, Mrs Klebold breaks down in tears.

'I just remember sitting there and reading about them, all these kids and the teacher,' she says.

'There's never a day that goes by where I don't think of the people that Dylan harmed... I think it's easier for me to say "harmed" than "killed."'

She then continues: ‘I would have felt exactly the same [as the victims’ families] if it was the other way round.’

Klebold has said that the Sandy Hook shootings of 2012 helped convince her to share her story and that she is donating profits from the book to mental health charities and research.

In 1999, Dylan Klebold and fellow senior student Eric Harris killed 12 students and one teacher at the Colorado high school before taking their own lives.

Dylan Klebol's large-scale attack also involved a fire bomb used to distract firefighters.

The choice to write the book was a difficult one for Sue Klebold, but she hopes the title will enable other parents to notice signs that their children might become violent. Signs she regrettably says she she missed.

‘It is very hard to live with the fact that someone you loved and raised brutally killed people in such a horrific way,’ Mrs Klebold explains in her interview with Diane Sawyer. ‘I think we like to believe that our love and our understanding is protective, and that if anything were wrong with my kids, I would know, but I didn't know, and it’s very hard to think of that.

Klebold goes on to say that before the shooting rampage, she was convinced that she was a good mother, and that her son Dylan could talk to her about anything. But the reality was something different.

‘Part of the shock of this was learning that what I believed and how I parented was an invention in my own mind, that it was a completely different world that he was living in,' she says.

In 2014 Crown Publishers, who are publishing Silence Broken, said that the book will, 'invite readers into [Klebold's] very private struggle of the last 15 years as she and her family have tried to understand the events of that terrible day and the role they ultimately played in it’.

At the time, it was the worst school shooting in the country's history before 2007, when 23-year-old Virginia Tech student Seung-Hui Cho went on a shooting rampage on the Blacksburg college campus, killing 32 people.

Five years later, 20-year-old Adam Lanza killed 20 students and six teaching staff at Sandy Hook Elementary School in Newtown, Connecticut.

Susan Klebold has previously described her feelings in an essay for Oprah Winfrey's O magazine and in interviews for Andrew Solomon's book, Far from the Tree.

Mrs Klebold and her husband Tom Klebold, have spoken little to the press following the Columbine tragedy, The New York Times reported in 2004, but did not move or change their names.

In her lengthy essay for O Magazine in 2009, Mrs Klebold wrote: 'In the weeks and months that followed the killings, I was nearly insane with sorrow for the suffering my son had caused, and with grief for the child I had lost.'

She continued: 'But while I perceived myself to be a victim of the tragedy, I didn't have the comfort of being perceived that way by most of the community.

The choice to write the book was a difficult one for Klebold, but she hopes the title will enable other parents to notice signs that their children might become violent. Signs she regrettably says she she missed

Eric Harris (pictured left) and Dylan Klebold (right) pictured in 1999

'I was widely viewed as a perpetrator or at least an accomplice since I was the person who had raised a "monster.'''

Mrs Klebold also told author Andrew Solomon: 'I can never decide whether it’s worse to think your child was hardwired to be like this and that you couldn’t have done anything, or to think he was a good person and something set this off in him.'

The killers' diaries from the time offered chilling details about their activities in the months before the attack. They had 'to do' lists, with each purchase of gasoline or a weapon marked off, and they had a hit list with at least 42 entries, all of them blacked out.

On a calendar entry for April 20, 1999, the time 11.10 is at the top - an approximate reference to the time the attack began.

Elsewhere in the calendar are notations including 'get nails' and 'get propane, fill my clips' and 'finish fuses'.

'Once I finally start my killing, keep this in mind, there are probably about 100 people max in the school alone who I don't want to die, the rest MUST (expletive) DIE!' Harris wrote in a journal entry from October 1998, six months before the attack.

A scrawled entry in Klebold's day planner apparently sketches out April 20, 1999, down to the minute, starting with a 6am meeting, a 10.30am 'set up,' an 11.12am 'gear up' and at 11.16am, 'HAHAHA.'