The murder of Rachel Nickell as she walked with her two-year-old son across Wimbledon Common one morning in 1992 was one of the most baffling and indiscriminate crimes ever dealt with by Scotland Yard.
The 23-year-old was knifed 49 times in an attack of appalling ferocity. But if the nature of the crime was not shocking enough, the bungled police investigation and prosecution which followed it certainly was.
In the wake of the murder, detectives launched a massive hunt for Ms Nickell's killer, with televised reconstructions, 3,000 people interviewed and a video-fit of the killer released.
Police were under huge pressure to catch him and quickly focused on one suspect Colin Stagg, a jobless man from Roehampton, who was known to walk his dog on the common. Someone said they had seen him on the morning of the stabbing. Sections of the media made their own inquiries and found Mr Stagg was a bodybuilder who lived alone and believed in an ancient pagan religion called Wicca.
Lacking firm evidence, police compiled a profile of the attacker with the help of Paul Britton, a criminal psychologist. Apparently convinced they had their man, officers prepared a "honey-trap" operation with Mr Britton's help in an attempt to get Mr Stagg to confess. An undercover officer, using the fictitious name Lizzie James, contacted Mr Stagg and tried to build a relationship with him in the next five months. She told him he could win her over only if he admitted to sharing her love of Satanism and child murder.
At one point, the officer said: "If only you had done the Wimbledon Common murder, if only you had killed her, it would be all right." He replied: "I'm terribly sorry, but I haven't."
However, police believed they had enough evidence to convict and Mr Stagg was arrested and charged. The case was thrown out in 1994 when Mr Justice Ognall said officers had "made a blatant attempt to incriminate a suspect by positive and deceptive conduct of the grossest kind".
Mr Stagg spent the ensuing years alternately dodging and courting media interest in him, fuelled in part by his admitting to possessing an axe and threatening behaviour following a row on the common in 1995. Ms Nickell's partner and son, meanwhile, moved abroad. A review of the inquiry failed to uncover new leads, despite police flying to New Zealand to interview a suspect, and it was scaled down in July 1997 after the Yard had spent 3m.
But in April 1998, officers began looking at links between the Nickell murder and 200 others. A year later, they reopened the file as part of a review of all unsolved murders in London. In 2002, the Yard brought in a cold case review team, which used modern DNA techniques and looked at witness statements.
In 2003, police said they had found a male DNA sample which ruled out Mr Stagg. In November 2004, they announced a new lead in the hunt for Ms Nickell's killer. Robert Napper, 40, was not questioned until July 2006, by which time Mr Stagg was seeking compensation and damages. The Home Office agreed to pay up in January this year.Reuse content