FTR, I don’t think longer sentences against individual perpetrators is the solution. There are always more poor kids to pull into the gang.

The only way to successfully deal with violent gangs is actual good investigation; implicate the people in charge, and put them in jail instead of their pasties. In the USA they’d use RICO to do so if they wanted to, which they don’t. Here in Canada, I’m not sure which law would be the most effective route, but it probably doesn’t matter anyways