The Vigilantes

There's a sudden spike in murders in Philadelphia, but no one seems to mind much because the victims are street thugs and lowlifes. But Homicide sergeant Matt Payne gets a feeling that there's more going on than just bad guys burning one another. In fact, he starts seeing signs that these guys are maybe getting whacked by professionals, from out of state, maybe even from out of the country.
Then comes the unexpected: copycats. Vigilante groups claiming credit for the killings, even though Payne knows that isn't true. As the police department tries to rein in these groups, the public protests--they "like "what they think the vigilantes are doing. The mayor hurriedly forms a special task force, led by Payne, but Payne knows he's in over his head. If Payne and his colleagues can't figure out who's behind this very soon . . . the violence could overtake them all.