Who directed the film Steven Spielberg cast Heather O'Rourke in where she had the line "They're here!"? 
Heather O'Rourke:  Spielberg cast her as Carol Anne Freeling in the horror film "Poltergeist" (1982), where she had the movie's most recognizable line: "They're here!" Poltergeist (1982 film): Poltergeist is a 1982 American supernatural horror film directed by Tobe Hooper.
Tobe Hooper