Question about the thugs at the complex (Spoilers)

I got a little confused at the part where the gun fight breaks out.

Were the ones attempting to steal the drugs from the opposite complex across the courtyard (if we call that a courtyard), or did they travel from far away?

And the ones dropping cinder blocks from the roof. Who were they? I thought most of the thugs at the complex knew Dheepan and would not purposely hurt him?