What should i do about gangs and their criminal behavour?

I moving soon but I feel I need to do something. I dont know why they have to hang out at the back of the building even x 3 times a day in groups. (They are loud about it as well and have broken my car mirror on purpose and I think have overheard them considering a break in). Its probably private property but its a very open with no gates and its has appartments like mine.


I called the guards about them but they are always gone when they come and since this the guards come hardly at all despite a car i was hoping to sell having been stolen in the past from here. the guards attitude is somewhat its precoutious to be living here as well so they tend to leave them to it.