Choker(2005)

They Are Here....Hud Masters a serial killer on death row has his execution faked by a clandestine government organization in exchange for an extension on his life. Hud is injected with an alien fetus enabling him to find hunt down and kill a rogue alien race that have deserted their world and have inhabited human hosts to stay alive. With the help of Special Agent Logan and the Alien police Hud must race against time - and his inner demons - as he defends the human race from aliens who themselves must fight against extinction.