The Body Stealers

Classic British sci-fi film starring Patrick Allen as Bob Megan, an investigator called in to solve the mystery of several paratroopers who have disappeared in a cloud of red mist. He soon uncovers an extra-terrestrial plot by aliens from the planet Mygon to steal men from Earth to impregnate Mygonian women and save their civilisation from extinction. Sean Connery's brother Neil co-stars as Megan's sidekick Jim Radford.