Rachel Nickell: the Untold Story – the horrific case at the heart of a new ITV documentary

A new ITV documentary, Rachel Nickell: the Untold Story, looks back at the shocking case and the controversial police investigation.

Using the services of a forensic psychologist, the Metropolitan Police thought they had their killer in local man Colin Stagg who regularly walked his dog on Wimbledon Common.

However, Stagg was entirely innocent and the investigation's lengthy focus on him meant that the real killer remained at large.

The ITV documentary is fronted by Fiona Bruce – who covered the story as a young TV reporter – and provides fresh interviews with Stagg and other key personnel involved in the case.

Find out more about the story behind the case below. Rachel Nickell: the Untold Story airs at 9pm on ITV this Thursday 8th March.

Who was Rachel Nickell?

Rachel Nickell was a young mother who was murdered on Wimbledon Common on 15th July 1992. She was stabbed 47 times, so brutally the shaft of the knife bruised her skin in places. Her two-year-old son witnessed the crime and was found clinging to her body.

What happened next?

A massive police hunt ensued, but little useful evidence emerged, and there was no DNA evidence. The police instead sought to create a psychological profile of the likely killer, in a move which said to have been influenced by crime series such as Cracker. Forensic profiler Paul Britton was tasked by police with developing a likely profile of the perpetrator, which led police to turn their attentions to one man: 29 year old Colin Stagg.

Why was Colin Stagg considered a suspect?

Stagg was believed to have fitted the police profile, and was identified by neighbours after an appeal on BBC show Crimewatch. His flat was adorned with strange iconography including pentangles – a five pointed star with occult-like meanings – but, as he tells the ITV documentary, these were actually the work of his brother, a heavy metal fan, who had previously occupied the flat he lived in.

He was arrested, and in the course of his questioning he admitted to indecent exposure on Wimbledon Common, a case which went to trial and saw him receive a fine. This meant that the newspapers called him an offender – some used even stronger language like “pervert” in their coverage.

Stagg repeatedly denied any involvement in the Rachel Nickell killing, so the police tried another tactic: a honey trap. An undercover female police officer codenamed “Lizzie James” from the Met’s Special Operations Group wrote to Stagg and tried to elicit evidence of sexual deviancy, and even to admit to murdering Rachel Nickell. Using this evidence, he was then charged.

However the Old Bailey judge threw out the case, attacking the police operation as “a blatant attempt to incriminate a suspect by deceptive conduct and the grossest kind.” As Stagg tells the documentary, he was sucked in by "Lizzie James's" approaches, only realising afterwards what was happening: “It made sense – why would an attractive woman be attracted to me?”.

Because the police said they were not looking for any other suspects – and refused to apologise to him – the finger of suspicion continued to point to Stagg even after the case was thrown out. As he states in the ITV documentary, he feared for his life, expecting a vigilante attack at any moment. It would be 14 years before the real killer of Rachel Nickell was convicted.

How did they catch Rachel's real killer?

Fourteen years after Colin Stagg was acquitted in 1994, the real killer was found: Robert Napper, a paranoid schizophrenic with Asperger’s Syndrome, admitted to killing Rachel. While the police were focusing on Colin Stagg, Napper had killed another woman and her child – Samantha Bisset and her four-year-old daughter Jazmine in November 1993. He was convicted of the murders, and in 2008 he was finally convicted of killing Rachel Nickell.

Newly developed techniques found a trace of paint from his toolbox in the hair of Rachel’s son. Napper pleaded guilty to Rachel Nickell’s murder on the grounds of diminished responsibility and was ordered to be held indefinitely at Broadmoor Hospital.

What happened to Colin Stagg?

The police apologised to the families of Rachel Nickell, Samantha Bisset and Colin Stagg for their failures in their investigation. Stagg was awarded substantial damages from the Metropolitan Police and has been exonerated as an innocent man – but a large chunk of his life has been overshadowed by this awful case. The Metropolitan Police’s use of psychological profiling in its investigations was significantly scaled back following the Nickell case.

Rachel Nickell: The Untold Story is on ITV in Thursday 8th March at 9pm