Sonic is more focused on recapturing then JUST beating up gang members, but if people are causing problems, he will whack them until they comply. Or get knocked out. One of those. Then its super speed to throw them into cells. Unfortunately there isn't A Ton of organization so some cells may end up overcrowded, but he figures that can be handled after the threats are down.

The criminals also probably have some rug burn or road rash because getting dragged by a three foot tall speedster.

He is more focused on criminals who are actually trying to hurt people than anything though and probably got some Nightshade just by virtue of poison not being very effective on him so he WILL take it as a challenge to knock them down when he gets hit.