Disturbing question ( possible spoiler)

It was almost the same way as the ending of this film.....apparently, there was a forest fire & the Bureau never found Gallagher's body, assuming it was burned up in the fire......Gallagher & Robert Stone [Gallagher's friend] were after the alien in the same way that Beck & Gallagher were after it as well....only thing that makes sense....the good alien inside Gallagher transferred into Robert Stone who took over the Gallagher identity...hope this helps.

Well, how ever the aliens arrived to earth in the first place, maybe they used some form of alien body while traveling here (but then again, where is the spacecraft), and that alien body held the metal pistol thing and was later destroyed in the fire as well!

Good movie!

Gallagher took over Beck's body after Beck's soul had left [died]. There was no reason for Gallagher to go back to his planet because he lost everything. In a sense, he re-animated Beck for his [Beck] family's sake. Beck's family reminded Gallagher of what he lost & didn't want history to repeat itself. As far as the daughter goes, I've been trying to figure that part out for years. The daughter sensed something different in both Gallagher & her father but never said anything. It can be interpreted as she saw something we didn't or just she was "special" as Gallagher said during dinner w/ the Becks. Best explanation I can think of.