To prepare for his role in this movie, Ben Foster asked one of his friends who is an ex-meth addict for guidance. The friend introduced him to a group of people who gave Foster an all-access pass into the lifestyle.
During filming, Santa Barbara County Deputy District Attorney Ronald J. Zonen provided copies of virtually every document in his file on the real life case and served as an unpaid consultant to the film.
Ben Foster risked his sight for the movie by adding glaucoma drops to his eyes for much of the shoot to dilate his pupils, making him appear to be high. He'd hide in the bushes at night and cover his eyes between takes to keep the lights from shining into them. He would also talk to writer/director Nick Cassavetes with his eyes closed.
The film was originally to be distributed by New Line Cinema. When they requested edits to the film that the director didn't want to make, they sold the film to Universal Pictures, which delayed release by a year, but kept the film intact.
This is the first of two films starring both Emile Hirsch and Ben Foster. They would later star together in Lone Survivor (2013). Ironically, they play enemies in this movie and close friends in Lone Survivor.
Anton Yelchin (who plays Zack Mazursky) voices the character of Jim Lake Jr in the series Trollhunters for 2 seasons. Following his death, Emile Hirsch (who plays Johnny Truelove) voiced the same character for season 3.
The trivia items below may give away important plot points.
Justin Timberlake's character "Frankie" is based on Jesse Rugge, who was convicted with Jesse James Hollywood for the real life murder of Nick Markowitz, which the movie is based on. Rugge was paroled in 2013 much to the dismay of the Markowitz family and Governor Brown. The character of Elvis, played by Shawn Hatosy, is based on Ryan Hoyt, the person Jesse James Hollywood hired to kill Nick Markowitz.
Filming was actually completed before Jesse James Hollywood was found and arrested in Brazil in 2005. When Nick Cassavetes heard the news of his arrest, he had the entire crew come back to shoot the new ending that is shown in the movie.