Sally Kirwin, and her toddler son, Tom, are murdered at Thames Glebe a small riverside park in Chelsea. Running from the site of the killing, the suspect, Clive Vesey Hart, collides with a woman walking her dog in the park; she then discovers the body.

She calls the police who arrive in time to arrest the suspect. Subsequent interviews by DCI Paul Perry and his assistant DS Phil Knight of the Met's Murder Squad, fail to sheet the murder home to Hart although, through examinations of his home and background, they are convinced that he is the killer. Part of this conviction is brought about both by Hart's apparent obsession with Jack-the-Ripper (he has a considerable library of books about him) and their discovery of a series of bizarre and increasingly overtly crude and suggestive letters that Hart has exchanged with 'Candy, a 'mail-order' correspondent whom Hart has contacted through a magazine 'Connexions' but has never met - much as he has tried.

Perry, without sufficient evidence to charge him, has to release Hart. New lines of investigation must be adopted. With the aid of a psychological criminal profiler, Dr Angus Albion (brought in by Perry's boss) it is decided to tap into the correspondence and, by eliciting Candy's help through the editor of 'Connexions', to embark upon a process whereby in exchange for promised sexual favours from her he will be inveigled into admitting that he killed Sally Kirwin.

Over a long period the interchange of letters is manipulated by Albion, using acquiescent Candy as the writer, to a point where she agrees to meet him at Thames Glebe. Having never met her, he has no reason to suspect the policewoman who actually turns up for the assignation. He, sexually roused by her, boasts that he killed Sally Kirwin whereupon he is seized by Perry and his men who have lain in wait.

Perry, a seasoned and dedicated officer, was always uncomfortable about the letter traps but against his better judgment, was coerced into the stratagem by his superior. But despite his scepticism he is mortified when the CPS refuses to allow the prosecution to proceed. In opening up further lines of enquiry the new technique of DNA analysis is used to examine Hart's 'body fluids' and it is found that he was not, after all, the murderer. The police have been wrong all along.

A fresh start has to be made, but without Perry. He takes all of the criticism and bears the blame for the failures, he is moved sideways, subsequently suffers a stress heart attack and retires from the police in his mid-fifties.

Perry is a wealthy widower, independent of police pay and pension, because his wife left him a sizeable fortune. He works hard at his recovery and grows fit and strong. Determined not to submit to a life of blank bleakness in middle-age he decides to make a complete break with London and to go as far away as possible. Having earlier in the story seen a display in a travel agent's window extolling Ayers Rock and The Olgas as destinations he travels to the heart of Australia.

In the dry, brash, alien desert town of Alice Springs he meets a New Zealand woman, Daphne Adams, ('Mrs Adams' as Perry instinctively calls her) a surgeon's widow, from Christchurch, New Zealand who is visiting with friends. Perry and she strike up a friendship and thereby make up a foursome, exploring the MacDonnell Range attractions, Ayers Rock and The Olgas, but the time comes for her to return home, leaving Perry with a few days in Australia before he, too, will return to London.

Before she goes she gives him a paperback book, one which her daughter had given to her to read on holiday and which she's finished with. He puts it aside but later, at a loose end, he picks it up. Reading through it desultorily he comes across a description of a murder which has unique aspects of the Sally Kirwin murder about it. The book, written by a woman, has been published in Christchurch, NZ. He realizes that whoever she i

Résumé
It begins on Monday 11 November 1985.Sally Kirwin, and her toddler son, Tom, are murdered at Thames Glebe a small riverside park in Chelsea. Running from the site of the killing, the suspect, Clive Vesey Hart, collides with a woman walking her dog in the park; she then discovers the body.She calls the police who arrive in time to arrest the suspect. Subsequent interviews by DCI Paul Perry and his assistant DS Phil Knight of the Met's Murder Squad, fail to sheet the murder home to Hart although, through examinations of his home and background, they are convinced that he is the killer. Part of this conviction is brought about both by Hart's apparent obsession with Jack-the-Ripper (he has a considerable library of books about him) and their discovery of a series of bizarre and increasingly overtly crude and suggestive letters that Hart has exchanged with 'Candy, a 'mail-order' correspondent whom Hart has contacted through a magazine 'Connexions' but has never met - much as he has tried.Perry, without sufficient evidence to charge him, has to release Hart. New lines of investigation must be adopted. With the aid of a psychological criminal profiler, Dr Angus Albion (brought in by Perry's boss) it is decided to tap into the correspondence and, by eliciting Candy's help through the editor of 'Connexions', to embark upon a process whereby in exchange for promised sexual favours from her he will be inveigled into admitting that he killed Sally Kirwin.Over a long period the interchange of letters is manipulated by Albion, using acquiescent Candy as the writer, to a point where she agrees to meet him at Thames Glebe. Having never met her, he has no reason to suspect the policewoman who actually turns up for the assignation. He, sexually roused by her, boasts that he killed Sally Kirwin whereupon he is seized by Perry and his men who have lain in wait.Perry, a seasoned and dedicated officer, was always uncomfortable about the letter traps but against his better judgment, was coerced into the stratagem by his superior. But despite his scepticism he is mortified when the CPS refuses to allow the prosecution to proceed. In opening up further lines of enquiry the new technique of DNA analysis is used to examine Hart's 'body fluids' and it is found that he was not, after all, the murderer. The police have been wrong all along.A fresh start has to be made, but without Perry. He takes all of the criticism and bears the blame for the failures, he is moved sideways, subsequently suffers a stress heart attack and retires from the police in his mid-fifties.Perry is a wealthy widower, independent of police pay and pension, because his wife left him a sizeable fortune. He works hard at his recovery and grows fit and strong. Determined not to submit to a life of blank bleakness in middle-age he decides to make a complete break with London and to go as far away as possible. Having earlier in the story seen a display in a travel agent's window extolling Ayers Rock and The Olgas as destinations he travels to the heart of Australia.In the dry, brash, alien desert town of Alice Springs he meets a New Zealand woman, Daphne Adams, ('Mrs Adams' as Perry instinctively calls her) a surgeon's widow, from Christchurch, New Zealand who is visiting with friends. Perry and she strike up a friendship and thereby make up a foursome, exploring the MacDonnell Range attractions, Ayers Rock and The Olgas, but the time comes for her to return home, leaving Perry with a few days in Australia before he, too, will return to London.Before she goes she gives him a paperback book, one which her daughter had given to her to read on holiday and which she's finished with. He puts it aside but later, at a loose end, he picks it up. Reading through it desultorily he comes across a description of a murder which has unique aspects of the Sally Kirwin murder about it. The book, written by a woman, has been published in Christchurch, NZ.