I'm clueless on that. In one of the cities I lived in a Federal task fotce came in to give local law enforcement help with a gangs cleanup. They did a good job of providing assistance. Prosecuted and sent away a lot of gang members. Even more left town and the ones left got very quiet. Federal and local PARTNERSHIP can be very effective.
Federal task forces come in
by request (unless pipelines are being protested under Obama). Commonly that is done over the interstate trafficking of drugs, human trafficking (sex slavery), or the movement of stolen goods in interstate theft rings, which reach the extent of federal jurisdiction anyway. Almost all of that involves either violation of Federal Law or interstate criminal acts or both.
It was done here during the oil boom, in part because some idiot TV producer thought it would be a good idea not only to advertise there was money and jobs in the oil patch, but that 'law enforcement were overwhelmed' and show masked felons stealing, claiming to be dealing drugs, and running prostitution rings and claiming to have hit the big time with no cops--which predictably brought every stinking criminal with any gumption or greed down on a community formerly of about twenty thousand, looking to steal, deal, or run their stable of girls.
A lot of criminals have found out otherwise, and have been imprisoned as a result, but I honestly hope the producer lives to a very old age in a blighted neighborhood someplace, without the fiscal resources to mitigate that (which is as nice as I can be on that score).
