Replicant (2001)

Jake Riley is working on the "Torch" case, a psycho serial killer, who kills women with kids and sets them on fire after they are dead. The killer calls Riley sometimes and now, that Riley retires, the killer has no person to play against anymore. The NSA comes into play here and offers a job to Riley. A replicant, or better a clone of the killer should help him find the real one, as kind of test if it works out. Now Riley is back on track, with a clone of the killer at his hand on the way to discover that nobody is born as murderer.