Death Wish - Lawrence block

This novel is about Edward Wright. Wife of Edward would not live with him, Edward reacted by pushing her off a flight of stairs, where she died. Before his wife said this to Edward, she had been boyfriend with a another man. The new man wanted to kill Wright because he killed his wife. He bought the wig and everything he needed to be like Wright. Then he imagined he would commit suicide and he bought a gun on a false license. The man who imagined as if he Wright returned to the real Wright and shot him with the gun. Finally the man took fingerprints to Wright on the gun so the man would not be accused of having killing Wright.