Murder of Rachel Nickell

An undercover policewoman from the Metropolitan Police Special Operations Group (SO10) contacted Stagg, posing as a friend of a woman with whom he used to be in contact via a lonely hearts' column. Over five months, she attempted to obtain information from him by feigning a romantic interest, meeting him, speaking to him on the telephone and exchanging letters containing sexual fantasies. During a meeting in Hyde Park, they spoke about the Nickell murder but Stagg later claimed that he had only played along with the topic because he wanted to pursue the romance.[2] Profiler Paul Britton later said that he disagreed with use of the fantasy-filled letters and knew nothing of them until after they had been sent.[3]

The undercover female police officer won Stagg's confidence and drew out violent fantasies from him but Stagg did not admit to the murder. Police released a taped conversation between the police-officer and Stagg in which she claimed to enjoy hurting people, to which Stagg mumbled: "Please explain, as I live a quiet life. If I have disappointed you, please don't dump me. Nothing like this has happened to me before". When she went on to say, "If only you had done the Wimbledon Common murder, if only you had killed her, it would be all right", Stagg replied: "I'm terribly sorry, but I haven't".[4] Believing, on the advice of the Crown Prosecution Service, that there was sufficient evidence to secure a conviction against Stagg for the Nickell murder, police arrested and charged him on 17 August 1993.

When the case reached the Old Bailey, Mr Justice Ognall ruled that the police had shown "excessive zeal" and had tried to incriminate a suspect by "deceptive conduct of the grossest kind". He excluded the entrapment evidence and the prosecution withdrew its case. Stagg was formally acquitted in September 1994.

Scotland Yard annually came under pressure for progress on the anniversary of the murder. Under new management, they began to collate evidence and files related to the case from 2000.[5]

In 2002, ten years after the murder, Scotland Yard used a cold case review team, which used refined DNA techniques only recently made available. A small team of officers and retired veteran investigators analysed statements from witnesses, reassessed files on a number of potential suspects and examined the possibility that the case was linked to other crimes. Officers compared the injuries suffered by Nickell with other attacks and consulted forensic scientists about improvements in DNA matching.[6] In July 2003, reports surfaced that, after 18 months of tests on Nickell's clothes, police had found a male DNA sample which did not match her boyfriend or son.[7] The sample at the time was insufficient to confirm an identity, but was large enough to rule out suspects.

In July 2006, the Scotland Yard team interviewed convicted murderer Robert Napper for two days at Broadmoor.[8] Napper, 40 years of age at that time, had been diagnosed as having paranoid schizophrenia and Asperger syndrome and had been held at the secure institution for more than ten years.[9][10] He had been convicted of the murder of Samantha Bisset and her four-year-old daughter Jazmine in November 1993, 16 months after Nickell's murder.[11] On 28 November 2007, Napper was charged with Nickell's murder. He appeared at City of Westminster Magistrates' Court on 4 December 2007, where he was remanded until another hearing on 20 December 2007.[12][13] On 24 January 2008, he pleaded not guilty to Nickell's murder and faced prosecution for the murder of Rachel Nickell in November 2008.[14] On 18 December 2008, at the Old Bailey, Napper pleaded guilty to the manslaughter of Rachel Nickell on the grounds of diminished responsibility. Mr Justice Griffith Williams said that Napper would be held indefinitely at Broadmoor because he was "a very dangerous man". (At the same time, Stagg received a public apology from the Metropolitan Police for their previous involvement and prosecution of him in regard the Nickell murder investigation).[15][16]

Following an investigation, the Independent Police Complaints Commission (IPCC) released a report, dated 3 June 2010, into the actions of the Metropolitan Police Force and their handling of the murder investigation. It described a "catalogue of bad decisions and errors" by the Metropolitan Police which had resulted in Napper being free to kill Nickell. It said that officers missed a series of opportunities to take the violent psychopath off the streets and suggested the lives of Samantha Bisset and her four-year-old daughter Jazmine would also have been saved if police had acted on tip-offs, including one by Napper's mother.

Rachel Cerfontyne, of the IPCC, said that police failed to investigate the 1989 report that he attacked a woman on Plumstead Common, in London and no record of the telephone call can be found. She said: "It is clear that throughout the investigations into the 'Green Chain' rapes and Rachel Nickell's death there was a catalogue of bad decisions and errors made by the Metropolitan Police. The police failed to sufficiently investigate after Napper's mother called police to report that he had confessed to her that he had raped a woman and, inconceivably, they eliminated Napper from inquiries into the Green Chain rapes because he was over 6ft tall. Without these errors, Robert Napper could have been off the streets before he killed Rachel Nickell and the Bissets, and before numerous women suffered violent sexual attacks at his hands". Detectives had decided to exclude anyone over 6' based on the description of a 5' 7" rapist, however there were conflicting witness reports of the rapist's height and Napper walked with a stoop.[26][27] The IPCC said no police officer would face disciplinary action because they had all retired and one key senior detective had died. Criminal prosecutions were not considered.[28]