Dean Koontz's "Mr. Murder" | 1998
Evil industrialist Drew Oslett, Jr., in an attempt to create a perfect warrior clone of a noted athlete, mistakenly takes a blood sample of Marty Stillwater, a writer, and creates Marty's double, code-name: Alfie. Years, late Alfie, a dead ringer for Marty, has become an efficient killing machine. But he has one psychological quirk -- he longs for Marty's family life. So he tracks down the Stillwaters and makes off with Marty's two daughters. Marty rescues his daughters and convinces hs wife Paige that he has an evil, superhuman twin. When the family goes into hiding, Alfie tracks down and kills Marty's parents. The police suspect Marty of committing these and several other murders perpetrated by Alfie. Marty and his clone finally square off and Alfie is destroyed in a fall from a roof. But when his double's flesh melts away without a trace, Marty has lost the evidence that he had a double who committed the crimes. So the Stillwaters flee to an island refuge.