6. The Long Island Serial Killer
Outfit: Police affiliation unknown
Crime: It might be a presumptuous stretch, but an unknown maniac has been dropping the bodies of women on a secluded Long Island Beach for several years now and many investigating the case think he might be a current or former cop. The Long Island Serial Killer typically targets women on the margins of society, like prostitutes and sex workers, and his crimes show detailed knowledge of forensics and police procedures.
He's up to eight victims now and he remains a ghost.