A school shooting is the type of event that shakes a community to its very core, Barbara Coloroso knows this all too well.

Coloroso is from Littleton, Colo., the town where 15 people died in the 1999 Columbine High School shooting.

Today, Coloroso is a bullying expert and author of the book, The Bully, the Bullied, and the Bystander.

She spoke to CBC Blue Sky host Garth Materie on Monday, just days after a school shooting in La Loche, Sask., left the community reeling.  

Coloroso said in the aftermath of a tragedy, like what happened in La Loche or Columbine, the community needs to come together to heal, but also to make some changes. 

"One of the things they can do is do something good for someone else. That will help them heal," Coloroso said. 

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Residents console each other at the memorial near the La Loche Community School in La Loche, Sask., on Jan. 24. Support is central to healing, according to bullying expert Barbara Coloroso. (Jason Franson/The Canadian Press)

She said that often shooters were tormented in some way by their peers.

She recommended that people can move away from being a bystander and do things like take a stand against bullies and make any new kids feel welcome. 

She said it's also important to realize that healing won't happen overnight.

"Over the next six months to a year, there's going to be an intense sorrow in that community, where everything that's done, good times and bad times, will be coloured with that intense sorrow," she said. 

It's important to recognize that grief but also come to terms with any guilt people may be feeling about what they did or didn't do before the shooting, Coloroso says.

"Guilt is not bad if we look at it in terms of 'what can I do now?' instead of beating yourself up over what you didn't do. That's past. Take that guilt and energize ourselves," she said. 

She said the community needs to support and embrace each other. In La Loche, people can look to elders for support, as well as others who went through the same experience. 

"It has to be an ongoing support of that community."