A handful of New York City cops have contended for the dubious crown of most corrupt ever in the 170-year history of the NYPD. There was Charles H. Becker, who met the electric chair in 1915 after he successfully ordered a hit on a gambler who had threatened to expose him as crooked. Or Louis Eppolito and Stephen Caracappa, who served as detectives while secretly doing the bidding of the Lucchese crime family. And then there was Michael Dowd.