Night Visitors (1996)

David, disillusioned scientist, works like a secret agent to break into the lab and remove the alien body and a video. Then the guards are incredibly lax and let him escape with the stolen articles. Out on the run, he leaves his son with his sister Kelly while he tries to get the mysterious box out to people he can trust. But the feds want the stolen articles back and run amuck in black suburbans without anyone noticing. When David is killed before they can retrieve the articles, they kidnap his son and use Kelly to locate the items. All along, they kill anyone who has any knowledge of their program or of the stolen articles to keep the contents secret. If the aliens are so smart, why are they constantly crashing into the Earth.