Almost all locations used for filming were the genuine locations where the events occurred. The tea shop where Honorah Parker ate her last meal was knocked down a few days after the shoot ended. According to director Peter Jackson, when they got to the location of the murder on the dirt path, it was eerily quiet; the birds stopped singing, and it didn't seem right. So they moved along a couple of hundred yards.
Juliet Hulme was revealed to be mystery writer Anne Perry who came forward and revealed her real identity in 1994 during the making of the film, but all attempts to find Pauline Parker failed. In 1997, Pauline Parker was finally traced to a rundown cottage on a farm near Strood, Kent, England, where she currently runs a children's riding school. Since assuming the name of Hilary Nathan, she has become a devout Catholic and devoted her life to handicapped children.
Since the Parker-Hulme murder had been an infamous crime that was strongly sensationalized in New Zealand history Jackson decided rather than do a film that would be a historical look back at the crime to instead create a drama about Parker and Hulme's intense friendship. In addition to reading Pauline Parker's diary Jackson and company undertook a nation wide search for anyone who had known the girls and interviewed them to get a closer look at their lives.
Up until 1973, the year Homosexuality was removed from the Diagnostic and Statistical Manual of Mental Disorders (DSM-III), it was thought of as a mental disorder and associated with deviant behavior which included, but was not limited to, murder. Because of the closeness of Hulme and Parker's friendship, there was a lot of speculation about whether or not they were lesbians. When Hulme was asked during the trial if she and Pauline had had sex, she replied, "how can we have sex? we are both girls."
When Juliet Hulme is introduced in the movie, it depicts her being called down by both her French and Art teachers. However, none of Hulme's instructors ever spoke to her harshly or even punished her. In fact, the opposite was true. According to classmates of Hulme, because her father was Rector of Canterbury University College and her family was English, she was treated very well by students and instructors alike. Girls Hulme attended classes with have stated in interviews that when a group of them got caught in mischief, they would simply have Hulme say it was her idea and there would be no consequences. Hulme's instructors gave her special allowances based on her father's position, even though he was not well liked by his colleagues, and Hulme's classmates found her very exotic because she was from England.
In New Zealand, the film was given the PG rating. But in the United Kingdom, the film was given a higher rating and was giving the 18 certificate, for the film's graphic murder scene and sexual content.
The film was later parodied in the 20th season of the long running animated comedy "The Simpsons". In Lisa the Drama Queen (#20.9) Lisa Simpson becomes friends with an intelligent girl named Juliet Hobbes and they both create a fantasy world and Marge decides that Lisa is not to see Juliet anymore, when Marge believes that their friendship has gone too far. Emily Blunt whom provided the voice of Juliet Hobbes, later provided the voice of Juliet in the animated 2011 film "Gnomeo and Juliet".
When Pauline visits Juliet at the hospital, she admires the red knitting on which Juliet is working. Juliet tells her "it's for you." Several scenes later, when Juliet and Pauline are seated on the bus during the "The Ones That I Worship" poem, Pauline is wearing the now-complete red sweater.
In 2015, Peter Jackson was speculated to direct an episode of the revived series of "Doctor Who". Sylvester McCoy, whom was the 7th incarnation of The Doctor played Radagast in The Hobbit trilogy which Jackson directed all 3 films and wrote the screenplay. Benedict Cumberbatch whom provided the voice of Smaug in the trilogy, played Sherlock Holmes in the TV series "Sherlock" which was created by "Doctor Who" showrunner Steven Moffat. Former "Doctor Who" showrunner Russell T. Davies had originally wanted Kate Winslet to play recurring character River Song in the series, but Alex Kingston was cast instead. Kate Winslet had worked with Russell T. Davies in the 6-part science fiction mini-series "Dark Season" which was broadcast on Children's BBC in the UK in 1991.
The trivia item below may give away important plot points.
How unbelievable it may seem, the actual real life murder was much more violent than depicted in the movie. PJ doesn't show us much and does an amazing job with sound, but eventually only the first eight blows are depicted in the film. The real Honorah Parker suffered around 45 different wounds on her face and skull, and had been found face upward as opposed to what was shown in the movie. Furthermore, she had been held down by the throat during most of the attack.