This solution should still work... have 6 unmarked police-cars cruise around, each containing 4 plainclothes police-officers carrying baseball-bats. Then they scout for loners or small groups wearing-black...
While simultaneously carrying-out surprise raids on the homes of unlucky rioters whose addresses are on-file, planting narcotics and whatever-else... Some can be 'framed' for murder. Then call on-duty officers to the scene.
Welcome to Democrat Mayor, John Daly's Chicago in 1968. All rioting and protesting in the city stopped after two nights.