My dad is asking me about a movie, he only saw the second half to. It sounds like there are aliens that have come to earth as assassins with bombs biologically inside themselves. The only way to find out is to cut the person open and see the bomb inside. Near the end of the movie a flying saucer is discovered with a human dead inside of it. An alien had been living in place of this human fooling everyone. Once confronted the alien explodes in a massive fireball.

Is this enough information for someone to figure this out? I hope so! Thanks.

Sounds like,.

Impostor

view trailer
http://www.youtube.com/watch?v=NVsNxKjmTlY