The Murderers: Badge of Honor Book 6 By W.E.B. Griffin

A Philadelphia narcotics cop is shot dead in his home. A bar owner's wife and partner are gunned down during an attempted robbery. And in a beautiful mansion, a young woman dies of a heroin overdose. At first the crimes seem unconnected. But these four deaths are about to trigger a massive convergence of corruption, cops, and the mob that could tear the Philadelphia Police Department apart from the inside out. All the way to the top.