The broad facts are well known but Graham's workmanlike account fills in a wealth of detail. The Hulme household was virtually dysfunctional, in the sense of providing what a teenage girl needed emotionally. Juliet's health was poor and she spent a large amount of time separated from her parents.
Her father was a very odd fish, a scientist who later went on to play a leading role in developing Britain's hydrogen bomb, and who came to New Zealand as rector of Canterbury University College. Her mother, who was a part-time marriage guidance adviser who broadcast on family matters, was having an affair with the lodger who was by her side throughout the girls' trial.
Parker's father had abandoned a previous wife and family and was not legally married to Pauline's mother, a state of affairs rather more shameful over 50 years ago than it is today.
Graham's research is thorough and he has been reluctant to let any of it go to waste. Did we really need to know the architectural history of Christchurch Central Police station or that Britain's civil defence budget rose from £9 million to £51 million in 1938?
He does, however, present a convincing picture of the moral and social climate of the Christchurch of the time, a background against which the murder must have seemed beyond belief. But if this book is strong on the background, the essential fascination of the case is, as Peter Jackson realised, the unlikely and fervid relationship between the girls.
They created a classic folie a deux, inhabiting a fantasy world in which they were creatures of unique genius and beauty. They dreamed of marrying film stars, of being opera singers and great writers. Such runaway escapism is common for teenagers but Hulme and Parker had no brakes. When Parker's mother seemed to be the bar to their being together when Hulme was due to leave New Zealand, the idea of killing her gave them few qualms. The attack was ferocious and their attempts to present it as an accident were laughably clumsy. Their continued lack of remorse and the grotesque lack of reality in their assessments of their own talents and intellects chilled those who dealt with them.
Insanity seemed an explanation but given their clear understanding that their actions were wrong it was never likely to be accepted as a legal defence. Graham is a barrister and we are given a thorough grounding in the relevant law and he is clearly as fascinated by the conduct of their trial as by the crime.
Guilty verdicts were inevitable and the two served jail sentences that seem remarkably short by current standards.
Graham tracks what can be known of their subsequent lives which hit the headlines again when Hulme was discovered to be a best-selling thriller writer under a pen name.
The fact that the author of the crime stories was an actual murderer did wonders for her already solid sales although, if the extracts Graham prints are typical, the writing hasn't developed much since she wrote her reams of adolescent tosh.
Graham casts a cold forensic eye on Hulme's later accounts, in which she distanced herself from the murder and left the responsibility to Parker who continues to live a very private life.
But for all the research and the investigations of psychological states and personality disorders the truth is elusive. The mystery remains of how these girls found it in themselves to commit a staggeringly brutal murder without compassion and apparently without denting their belief that they were "so brilliantly clever".
John Gardner is an Auckland reviewer
