I agree with you. I think it is important in those kinds of investigations to talk to everybody.
I don't know whether you are aware of it, but you might be interested to know that the International Centre for the Prevention of Crime produced a report for the Montreal police in collaboration with the University of Montreal. It looked at urban riots and at the kinds of events that happened in Britain, France, and Australia after the Montreal riot. That report is available in French. I can make sure it's sent to you. It is an analysis of what happened in France after les émeutes in 2005 and of what happened in Australia. It tries to analyze the conditions that resulted in the riots that took place.
I hope in some sense it's something that speaks to those issues too.