A retired FBI agent was indicted on murder charges Thursday for allegedly taking bribes from a mobster to supply him with inside information that led to four underworld slayings in Brooklyn. R. Lindley DeVecchio, 65, was arrested in a case of "confidential leaks, payoffs and death" dating back two decades, District Attorney Charles Hynes said. DeVecchio pleaded not guilty and was released on $1 million bail. He did not speak at his arraignment. One of the two alleged mob hitmen behind the slayings was jailed without bail. The other was in Florida, awaiting extradition.