Kripke had previously pitched the series to Fox executive Peter Johnson, and when Johnson moved to Wonderland Sound and Vision as president of TV, he contacted Kripke. Johnson soon signed on as co-executive producer, as did Wonderland owner McG as executive producer, with the production company set to make the pilot episode. Before it could be filmed, however, script issues needed to be dealt with. Originally, the brothers were not raised by their father, but rather by their aunt and uncle. Thus, when Dean comes to Sam for assistance in the pilot episode, he has to convince him that the supernatural exists. However, Kripke realized that this made the backstory too complicated and reworked it with Peter Johnson so that their father raised them to be hunters. The script went through many additional revisions. One of the original ideas was for Sam's girlfriend Jessica to be revealed as a demon, which prompts him to join Dean on the road; however, Kripke felt it was more appropriate for Sam's motivation to be Jessica's death, so he had her killed in the same manner as Sam's mother, making them the "right bookends". Other revised concepts include Sam believing Dean to be a serial killer who murders their father and their father dying in Jessica's place. Filming for the pilot episode was greenlit after director David Nutter, who previously had worked with Kripke on "Tarzan", signed on. When the series was eventually picked up, the studio brought in Robert Singer as executive producer, as it wanted Kripke to work with someone with production experience. Due to his previous work on "The X-Files, "co-executive producer John Shiban was also hired to help design the series mythology. Kripke had the series planned out for three seasons but later expanded it to five and hoped to end it there on a high note.