Someone's Knocking at the Door

Someone's Knocking at the Door is a 2009 American comedy horror film co-written, directed and produced by Chad Ferrin. The film stars Noah Segan, Andrea Rueda, Ezra Buzzington, Jon Budinoff, Silvia Spross, Elina Madison, Ricardo Gray, Lew Temple, Vernon Wells, and Timothy Muskatell. The film follows a group of drug-addled medical school students, Justin, Meg, Sebastian, and Joe, who are targeted by John and Wilma Hopper, a married sexually sadistic serial killer couple from the 1970s who rape their victims to death.

Synopsis from Wikipedia, CC BY-SA 4.0. Everything below written here.