Wayne Dumar was a detective from the 7-4, business partner of disgraced cop Bob Cerullo, and a dirty cop in his own right. Back in the day, he had a bad habit of shaking down suspects for cash and selling stolen property. When things got too crazy, Cerullo shot Dumar to cover up his own dealings and made it look as though Dumar had committed suicide because he'd known the cops were on to him. When Cerullo later killed a hitman, Jay Fleckner, and planted a gun owned by Dumar in Fleckner's hand to make it look like he'd shot him in self-defense, the police at Manhattan Homicide went digging through his record and found evidence that he'd killed Dumar.