FRESNO, Calif. (KFSN) -- 17-year-old Dylan Klebold barged down the stairs on the morning of April 20th, 1999.
"All he said was bye, and he slammed the door," Sue Klebold recalled the chaos which followed.
13 people were shot and killed by her son Dylan Klebold and Eric Harris at Columbine High in Littleton, Colorado. More than 20 others were injured.
"They think its kids with trench coats and Dylan and Eric had trench coats," she said.
Sue Klebold told me, for years, she couldn't show her face in public.
"It was horrible. I had never had an enemy in life. I had never known what it was to be hated and judged," she said.
In 2016 Klebold published "A Mother's Reckoning: Living In The Aftermath of Tragedy." Proceeds from the book benefit mental health organizations.
"Dylan's death, although he killed other people, it was a suicide," she said.
Sue Klebold wishes she could have talked less and listened more.
"Stop trying to fix kids problems when they're telling you what they're feeling," she said.
Her powerful words kept the crowd's attention at Fresno City College.
"I think opening that dialogue, I mean it was a very uncomfortable place to be in, to participate in and I think to solve problems like this you have to face the problem itself," said Patrick Schulteis.
"It was just interesting how she was basically telling his side of the story," said Pazau Moua.
Sue Klebold talked about the importance of noticing sudden changes in your kids' behavior and even sleep patterns.
"I believe there were warning signs but this was 20 years ago. The fact that he wrote a violent paper, the fact that he had gotten in trouble at school two years before the event," Klebold said.
"He wrote in his journals he wanted to die by suicide. He never wrote about wanting to kill," she said.
But Sue Klebold says she had no idea until detectives shared his journal.
Sue Klebold says it can be difficult to determine if your child's behavior is that of a moody teen or if they are facing more serious issues so it's important to ask about their feelings.
Mother of Columbine shooter speaks at Fresno City College almost 20 years after massacre