I'm coming late to this subject, but at first glance it seems to me that the headline - children and youths - isn't a good descriptor for the scope of the study: 24 years of age and under. When you consider that most of the dead or wounded gangbangers/druggies in our major cities fall into this category, and that a good chunk of them are members of what could be called immigrant gangs, then the headlines and the other claims can be seen in a different light.
Ottawa is a pretty small city as far as urban centers are concerned, but it had a heck of a lot of shootings, and as you can see from this story, none of them appeared to be "accidents", and most involved victims (and accused persons) from immigrant communities.
http://www.cbc.ca/news/canada/ottawa...view-1.3870975