Asylum seekers intimidation?

I noticed again yesterday how many of the Iraqi Kurds are loitering aimlessly in the main big local park were I live.I sometimes have to p through it and the group is getting larger.It's known some of these characters are dealing drugs and also carry weapons(knives)They are wearing expensive clothes and always surrounded with young kids(girls)and I know people have complained that the park has been overrun by these characters. Local youths avoid it because of confrontation and intimidation by these people.,what can be done about it if the police dont put their foot down.