More than 50 years on from what is arguably New Zealand's most famous murder, the Parker and Hulme case and the lives of the two girls convicted of the grisly murder continue to generate intense interest.
Juliet Hulme, 15, and Pauline Parker, 16, were two friends who conspired to kill Pauline's mother Honorah because they believed she would force them apart by not letting her daughter join Juliet, who was leaving the country with her parents.
On the afternoon of June 22, 1954, the girls lured Honorah to Victoria Park in Christchurch's Port Hills, under the pretence of a walk. Down a secluded path, they bashed her to death by hitting her more than 20 times with a half-brick inside a stocking.
In a murder case that transfixed the nation, the girls were arrested for murder and tried in the Supreme Court of New Zealand in Christchurch.
They were found guilty and sent to separate prisons.
After 5 1/2 years, in November 1959, they were released - free to start a new lives under new identities.
While it is a common belief that the girls were to never communicate again as a condition of their release, this is untrue.
Juliet, who changed her name to Anne Perry, was released without condition and boarded a plane bound for Italy to be reunited with her father and stepmother and later her mother.
Pauline was released subject to initial control of where she lived and worked.
She changed her name to Hilary Nathan and lived in Auckland while finishing a Bachelor of Arts degree and in 1965, when her release became unconditional, she immediately disappeared from the country.
Incredibly, both women have chosen to settle in Scotland where they lead largely reclusive lives.
Perry lives in the remote fishing village of Portmahomack, 50 miles north of Inverness. A successful crime writer, she has sold more than 25 million copies of her books.
Nathan, who has previously worked as an English teacher and with the mentally ill, has settled in the Orkney Islands.
A devout Roman Catholic, she leads a life of solitude similar to that of a nun, her sister Wendy said in a 1997 interview.
Matricide, the killing of a person's mother, remains an incredibly rare crime, particularly by a young person.
That along with the girls' disturbed relationship as teenagers and Juliet's career as a crime writer following her release have all added to the public's ongoing fascination with the case, says Peter Graham, a crime writer and retired barrister based in Canterbury.
He has just released a new book - So Brilliantly Clever - which delves back into the Parker-Hulme case.
"There's an X-factor with murders and some grab everybody's attention. This seems to have all the ingredients to make an interesting story," he says.
Graham has no reservations about reawakening public interest in the case through the book, which traces the girls' developing relationship, the murder, court case, imprisonment and lives following release.
"It's a book that needed to be written. It's public property I think - what they did was so horrendous."
However, when he approached Perry asking her to be part of it, she was furious to learn her past would again be in the spotlight.
In 2009 Graham wrote her a letter telling her about his plans to write the book and could he interview her?
He received no reply so, during a trip to Scotland that summer, he phoned Perry's home - and got a frosty reception.
"Do you have any idea how unbearably painful this is for me?" she said.
Graham pointed out that she had previously given several interviews to newspapers and magazines, what difference would one more make?
"I've forgotten everything anyway. I wish to have nothing whatsoever to do with you and your book," she replied.
He was unable to track down contact details for Pauline.
The book is named after an entry in Pauline's diary, in which she delights in the superior intelligence of her and Juliet in planning their future - "...we are so brilliantly clever".
It reveals perfectly the narcissistic nature of the girls' relationship that would become increasingly manic, says Graham.
In 1954 Hulme had moved to Christchurch with her affluent English family. There the arrogant and outspoken teen befriends working-class Parker at Christchurch Girls' High School.
Both unable to take part in sport at school because of childhood disease, they share a love of literature and the fantasy world they begin to create.
They quickly develop an intense and obsessive relationship psychiatrists would later describe as a mental illness shared by two highly intelligent, "dirty-minded" girls suspected of being lesbians.
Increasingly, Pauline spends most of her time at the Hulmes' house where the pair share beds, baths and 'the Fourth World' - a realm only them and a few chosen others can see.
When Hulme's parent announce their intention to divorce and move back to England, leaving Juliet with a relative in South Africa, the girls become hysterical at the thought of being separated.
But Hilda Hulme tells the girls Pauline can accompany Juliet to South Africa.
Believing Honorah Parker will stop her from going and force the girls apart, the friends plan to get rid of her and make a pact to sink or swim together.
"Why could mother not die? Dozens of people are dying all the time, thousands, so why not mother, and father too," Pauline writes in her diary.
Murder, in their eyes was "just a solution to a problem," says Graham.
On June 22, 1954, the girls and Honorah Parker set out to Victoria Park in the Port Hills above Christchurch together for a walk.
They share afternoon tea at the kiosk and then head down an isolated path. When Honorah bends over to pick up a pink charm the girls have left on the ground as bait, Juliet and Pauline bludgeon her to death using a half brick in a stocking.
"Pauline bashed away mercilessly but her mother was slow to go down.
"Juliet grabbed the loaded stocking from Pauline and landed further furious blows on Nora's head. Blood was spraying everywhere. Her resistance was weakening," writes Graham.
Pathologist Colin Pearson later reported there were 45 external injuries - 24 wounds to the face and scalp and fractures to the front of the skull. It was later revealed that the brick came out of the stocking from the force of the blows.
Their plan to kill Honorah was carefully outlined in Pauline's diary and following a police investigation the girls were quickly arrested for murder.
Shock over the crime spread around the country and the world as media converged on Christchurch for the trial at the Supreme Court of New Zealand.
Astonishingly, throughout the trial the girls appear disinterested in the proceedings and instead spent most of their time whispering happily to each other - "They were so pleased with themselves", says Graham.
Psychiatrists who had assessed the girls gave evidence that they suffered from paranoia, attachment anxiety and narcissism, but not insanity, as the defence team attempted unsuccessfully to prove.
They were always aware that what they were doing was wrong, says Graham.
After deliberating for two hours and twelve minutes, a jury found them guilty of murder.
Graham says that if they were tried today, it was likely the outcome would have been the same. Insanity is a very rare and difficult defence to prove.
The pair were saved from hanging only by their young ages, but far greater punishment for the girls than the prison sentences before them, was being separated.
Pauline was sent to Arohata Borstal north of Wellington and Juliet to Auckland's notorious Mt Eden Prison.
The female police officer who escorted them from the court was shocked to overhear Juliet whisper to Pauline, "The old girl took a bit more killing than we thought".
When the officer took her to task over the remark, Juliet jeered back, "Oh aren't we the perfect little policewoman".
Examining the case more than 50 years on, Auckland forensic psychiatrist Ian Goodwin says he has no doubt the girls were "quite mad" - convinced they were superior beings living in a world of their own creation.
But if assessed today, their mental diagnoses would probably be different as specialists were more likely to take in account more their stage of development, he said.
"I think they would be a bit more understanding in terms of what we know about adolescent brains. All 15-year-olds are narcissistic. It's a bit dangerous to apply adult psychological concepts to young adults," he told APNZ.
The concept of "temporary insanity" does not exist in our law, Goodwin says.
Some theories of narcissism say it arises out of attachment disorder.
Judith Morris, an Auckland-based registered psychotherapist specialising in children and adolescents, says this disorder develops when children lose security and trust in adults because their basic needs are not met as a young age.
After the birth of her brother in 1944, Juliet Hulme developed pneumonia and bronchitis. She was sent to live with strangers in London, not seeing her parents for long stretches of time.
In 1947, aged 8, she was sent to live with friends of her parents in the Bahamas, and months later to the Bay of Islands in New Zealand.
"You lose trust and you feel you're not worthwhile," says Morris of sufferers of the condition.
As a coping strategy they can become "desperate to hang onto whoever they feel they can trust" and some themselves off from adults, she told APNZ.
"For those who are insecure it's a way of taking control and making their environment predictable again."
An over-inflated ego and outbursts of violence are also typical for those with the disorder, she says.
For crime writer Anne Perry, her dark past as Juliet Hulme has paid.
The ongoing international interest in the murder has added to her allure and mystery as an author writing from personal experience.
Perry has often spoken in interviews about redemption - sometimes her own.
Three months into her prison sentence she knelt by her bed and prayed about her crime: "I just begged for forgiveness. I said I was sorry again and again and I meant it," she reportedly said in an interview with the Daily Mail.
But she has also talked about blocking the horrific crime from her mind and refusing to remember her part in it.
"I would just torment myself (if I did that) and that wouldn't help anybody," she told the Daily Mail in 2006.
Did she think about Honorah Parker?
"No. She was somebody I barely knew," she said.