Should the Yorkshire Ripper really be in Broadmoor? Or was he not mad at all, but a coldly calculating killer? David Peace on a case that remains full of strange anomalies.

Carol Wilkinson was murdered in Bradford in October 1977 on the same day that the body of Jean Jordan was discovered in Manchester. Wilkinson's injuries initially caused police to think that she was the sixth victim of the Yorkshire Ripper. But George Oldfield, then head of the Ripper Squad, changed his mind and, deprived of manpower by the hunt for the murderer, the Wilkinson inquiry was delegated to two inexperienced detectives. Jean Jordan became, instead, the sixth victim of the Yorkshire Ripper. Eighteen months later, 22-year-old Anthony Steel confessed to Wilkinson's murder. Steel was mentally handicapped and had been interrogated for two days before making his confession. The chief superintendent with overall responsibility for the charge against Steel was James Hobson. By this time, Hobson had also taken command of the Ripper Squad and would remain there until January 1981. On 28 February this year, the appeal court quashed the 1979 conviction of Anthony Steel for the murder of Wilkinson. Her case remains unsolved. More questions. No answers. No end.

The hunt for the man who would become the Yorkshire Ripper began in Leeds on 30 October 1975 with the murder of Wilma McCann. His first four victims were described by the police and press as "good-time girls" - prostitutes. But then, in June 1977, the Ripper killed a 16-year-old shop assistant. This murder caused public outrage, bringing intense pressure on West Yorkshire Police, pressure that was to increase with each murder and assault. In April 1979, the Ripper killed another "innocent girl" in Halifax. It was in the aftermath of this tenth death that the police decided to release excerpts from a cassette tape and letters that they believed had been sent to them by the Ripper.

No one who heard the tape will ever forget the Geordie voice that taunted the police and threatened to kill again. Nor will anyone ever forget the siege of fear it laid to the entire north of England. The tape convinced senior Yorkshire detectives that the Ripper was from Wearside. They believed that the tape and letters contained information that only he, the killer, could have known. They also believed the Ripper had left behind clues that would eventually help catch him, and so launched a million-pound publicity campaign to "flush out the Ripper". One clue was the reference in the first two letters to the murder of a woman called Joan Harrison in Preston, Lancashire, in 1975. This murder was now regarded by West Yorkshire Police as the work of the Ripper.

Three murders later, two uniformed policemen approached a parked car in Sheffield's red-light district on 2 January 1981. Inside it were a prostitute and her punter. The punter was Peter William Sutcliffe, a 34-year-old, married lorry driver from Bradford. He was not a Geordie. But, two days later, he confessed to being the Yorkshire Ripper.

Twenty-two years after the arrest of Sutcliffe for 13 murders and seven assaults, there is no end in sight for the communities he terrorised. Uncertainty remains as to how Sutcliffe could have done what he says he did and why, and how the police could have let him and why. Sutcliffe's trial at the Old Bailey and the subsequent review of the police investigation by Sir Lawrence Byford, the chief inspector of constabulary for England and Wales, should have answered the public's questions. Neither did.

Before he was arraigned, the crown prosecution and defence counsel had agreed that Sutcliffe was suffering from a paranoid schizophrenia that led him to believe he was on a mission from God. These divine instructions came from voices Sutcliffe had first heard when working as a gravedigger. Sir Michael Havers, the attorney general, was prepared to drop the murder charges if Sutcliffe pleaded guilty to manslaughter on the grounds of diminished responsibility. But Mr Justice Boreham, the trial judge, believed both prosecution and defence had accepted psychiatric evaluations based solely on the word of Sutcliffe himself, and that he had contradicted his original confession to police, when he had made no mention of either voices or missions. Justice Boreham ordered that it was for a jury to decide if Sutcliffe was himself a victim of his own uncontrollable madness, rather than simply a premeditated murderer. The jury found Peter William Sutcliffe guilty on 13 counts of murder and the judge sentenced him to life imprisonment. But given the initial plea-bargaining, it was an unconvincing trial, made only more so by Sutcliffe's eventual transfer to Broadmoor mental hospital.

Further public doubts about the West Yorkshire Police and their investigation into the Ripper case were not assuaged, either, by Home Office insistence that the Byford report remain an unpublished and classified document. The Home Office brought no pressure to bear for the arrest of the person responsible for the hoax letters and tape that had so misled the police. Nor did there seem to be any particular impetus to solve the murder of Joan Harrison, which police had included in the Ripper inquiry but was the one crime that Sutcliffe consistently denied.

There have now been 11 books devoted to the case of the Yorkshire Ripper, every one of which has managed at some stage to introduce evidence of contradiction or error. However, some books have been more useful than others. Deliver Us From Evil by David Yallop, published in 1981, listed a number of murders and assaults (including that of Carol Wilkinson) that the author felt Sutcliffe should be questioned about. In the years since his trial, Sutcliffe has indeed confessed to two of these assaults. Somebody's Husband, Somebody's Son by Gordon Burn and The Streetcleaner by Nicole Ward Jouve both made intelli- gent attempts to understand Sutcliffe and the time and place in which he lived.

It has been more than ten years since the last major book on the case. But policemen retire. Friendships fade. Pensions depreciate. Tongues loosen. Perhaps, then, it is not surprising that this year brings two new books. The Shadow of the Ripper is the result of its author's obsession with Wearside Jack, as the author of the hoax letters and tape is known. Patrick Lavelle has already published one book and a number of articles in the Sunderland Echo on his search for the hoaxer, and this latest book continues his dedicated research. Shadow of the Ripper contains much interesting information about the original investigation on Wear- side and offers a compassionate account of the life and death of Joan Harrison. Lavelle now believes Sutcliffe did kill Harrison, and did so in the company of Wearside Jack. Lavelle also believes Wearside Jack later murdered a woman called Julie Perigo in Sunderland in 1986. But much of this is not new.

Two days after Sutcliffe was found guilty, the Sunday Times published a three-page article, headlined "Did the Ripper have an accomplice?". The sources behind this suggestion appear to have been "senior police officers". The article was the first to link Sutcliffe to the Harrison murder via an accomplice who then produced the hoax letters and tape. These arguments were largely discredited by a later report in the same publication. However, both articles agreed on a possible connection between Harrison's murderer and the person responsible for the letters and tape.

Lavelle highlights many of the loose ends and unanswered questions surrounding the entire Yorkshire Ripper inquiry. However, the arguments are not well marshalled, and assume the reader to be already very familiar with the intricacies of the whole case. He is too concerned with the people who were originally suspected of being behind the hoax letters and tape, and the book would have been more persuasive if the evidence from the initial investigation and trial of Peter Sutcliffe had been set out first, in detail. The undoubted contradictions and anomalies in the case could then have been better exposed and tested against Lavelle's own theories. The book would also have benefited from an index and detailed list of sources.

Wicked Beyond Belief has 100 pages of sources, notes, references, appendices, a bibliography and an index, plus the obligatory "sensational" revelation. Michael Bilton was part of the Sunday Times Insight team responsible for the initial accomplice piece. He shares with Lavelle the same guide on the mountain: former detective superintendent Dick Holland, a senior member of the Ripper Squad from 1977 to January 1981, who also believes that Sutcliffe was linked to Joan Harrison, Wearside Jack and the hoax. Despite his continued friendship with Holland, Bilton has no place for the theories of his main source. His motive for writing this book is, rather, to "put flesh and bone" on the much-maligned detectives who tried to catch the Ripper. In his extensive research, Bilton had the "good fortune" to be given "privileged" access to the "secret" Byford report into the police investigation. However, as it is presented here, the report seems remarkably tame when set against the very human cost of the police failure to catch Peter Sutcliffe.

There are few new facts about the investigation itself in Wicked Beyond Belief that have not already been published in previous books or newspaper articles. Bilton does, I concede, reveal that one victim was not the virgin her parents believed her to be, and that she had also promised to have sex with her new boyfriend (source Dick Holland). True, he reveals that another victim had had an argument with her mother the night she died (source confidential). And true, he also reveals that an unmarried victim had had a number of lovers, but not many (source West Yorkshire Police).

That Bilton is so candid about the victims and their secrets stands in sharp contrast to his silence in regard to the police and theirs. In the 482 pages of this book, there is no mention of the wrongful conviction of Judith Ward for the murder of 12 people in the M62 coach bombing of 1974. Ward spent 18 years in prison before her conviction was quashed in 1992. The appeal court was told that Ward had changed her confession several times. The police and prosecution had then edited different parts together to construct a single, plausible statement. The prosecution also concealed other important facts from the defence. There is no mention in Wicked Beyond Belief of the role of George Oldfield in Ward's arrest and trial. Nor is there any mention of the wrongful conviction of Stefan Kiszko for the murder of 11-year-old Lesley Molseed near Ripponden, West Yorkshire, in October 1975.

Twenty-four-year-old Kiszko, who had physical and mental problems, was told that if he signed a confession he could go home to his mother. He would spend 16 years in prison before his conviction was quashed in 1992. Evidence that Kiszko could not have produced the semen found on Lesley Molseed's clothing was withheld during his original trial. There is no mention anywhere in Bilton's book of the part played by Dick Holland in Kiszko's arrest and trial. Yet both these cases helped propel the careers of Oldfield and Holland to the top of the Ripper Squad. These cases are of relevance to any understanding of the time and place of the Ripper's Yorkshire and that of the men who hunted him.

But as befits any book worthy of seria-lisation in the Sunday Times, Wicked Beyond Belief does have its "sensational" revelation. The retired detective chief inspector Desmond O'Boyle reveals to Bilton that Sutcliffe was wearing a "killing kit" at the time of his arrest. This included an inverted V-neck sweater, worn in place of underpants, with the legs placed inside the sleeves and the genitals exposed. For further comfort, Sutcliffe had also sewn in reinforced knee-pads. The killing kit was discovered only after Sutcliffe had completed his 15-hour confession to John Boyle, Peter Smith and Desmond O'Boyle at Dewsbury police station. Bilton claims the detectives bagged this killing kit for forensic examination but made no mention of it to any "senior investigating officer". Nor was any written record of it ever made. Really?

In his text notes and references, Bilton attributes this disclosure to a third and final telephone interview with O'Boyle on 13 March 2002. That, according to his own notes, would make it the last interview Bilton conducted with any member of the Ripper Squad. It is a great shame, to say the least, that Bilton did not see fit to reinterview his other sources in the light of this revelation.

The degree of premeditation involved in fashioning a "killing kit" makes a further and complete mockery of the psychiatric arguments that surrounded Sutcliffe's trial and his initial plea-bargain of diminished responsibility. Furthermore, the implications for all involved are grave. If O'Boyle's statements to Bilton are to be believed, a vital piece of evidence in the largest criminal investigation in British history was not disclosed. More questions. No answers. Half-truths drip-fed to us as sensation and scoop by media conglomerates while organisations such as Tough Justice - which campaigns against miscarriages of justice - work for nothing to free innocent victims such as Anthony Steel.

There are old men out there who know the answers to all the questions about the Ripper case. These men failed us once and, through their silence, they fail us again and again. These men can still right some of the wrongs done to the victims and their communities. There is still time, but it is running out. And yet, to the dead, we owe the whole truth and nothing but that truth.

Shadow of the Ripper, Patrick Lavelle, John Blake, 318pp, £16.99

Wicked Beyond Belief, Michael Bilton HarperCollins, 482pp, £18.99

David Peace is the author of the Red Riding Quartet - Nineteen Seventy-Four, Nineteen Seventy-Seven, Nineteen Eighty and Nineteen Eighty-Three (all published by Serpent's Tail) - four novels about the secret history of West Yorkshire during the reign of the Yorkshire Ripper and the rise of Margaret Thatcher