Problem neighbours

Other

I have a house in a mixed student / private residential street & up to now this has worked well. However,recently three houses up the road have been let by private landlords (through a letting agent) to the local council under some sort of homeless initiative scheme. The tenants include convicted burglars & arsonists. (The arsonist has had the fire brigade out on a number of occasions for burning furniture, his TV & next door's fence in the front garden). The police are called to one or all of the houses pratically every day for a variety of reasons, including noise & fighting. Understandably, all the neighbours are afraid to make official complaints for fear of reprisals. The letting agents are not interested when we ring them & complain.
Has anybody got any experience of similar problem neighbours & if so, what did you do, as I fear that soon the street may become a ghetto.