Rachel Nickell, mom stabbed 49 times in daylight, was also victim of 'catastrophic' police mistake

Warning: This article contains discussion of rape which some readers may find distressing.

It’s been 34 years since the horrific murder of Rachel Nickell, in which the 23-year-old mother was stabbed to death in Wimbledon Common, London, in front of her 2-year-old son Alex.

In a new documentary, detectives reveal how the murder could have been ‘prevented’ if it wasn’t for a ‘catastrophic’ police mistake.

The crime, of which Alex was the only witness, shocked the United Kingdom, and for months investigators had no leads. Meanwhile, the real culprit walked free due to a catastrophic police mistake.

Netflix is set to release the documentary The Murder of Rachel Nickell this Thursday, June 4, featuring interviews with Nickell's husband, André Hanscombe, and their son Alex, who is now 36 years old.

Just over a year after the murder, police arrested and charged Colin Stagg for the murder of Nickell, who was stabbed 49 times in broad daylight. However, the case against him was thrown out when flaws in the undercover 'honey trap' police investigation, which included undercover investigators exchanging sexual messages with Stagg, was thrown out by Justice Ognall in September 1994, and called inadmissible.

Rachel's murder 'could have been prevented' detectives say (Image: Netflix)

It wasn’t until 16 years later, when the Met Police had scaled down their enquiry and turned Nickell's murder into a cold case, that the real murderer, Robert Napper, was arrested. By then, Napper was in prison for a similar horrific crime.

In November 1993, Samantha Bissett and her four-year-old daughter, Jazmine Bissett, had been stabbed to death in their home in Plumstead. Napper was arrested for the murder a year later after fingerprints were discovered in the flat.

In December 2007 Napper was formally charged with Nickell's murder, when advances in DNA profiling identified him as a suspect.

However, a ‘catastrophic’ police error carried out years before the murders meant Napper had been left to walk free, even after raping several women years before he committed the heinous killings.

28-year-old Napper had been alerted to police three years before the murder of Nickell when a serial rapist began attacking woman, some with children present, in Southeast London. DNA had pulled out a suspect, and two woman had called police to say the artist sketch looked like Napper.

Police turned up at Napper’s house, asking him to come to the police station the next day, however, he didn’t turn up. Later, police disregarded him as a suspect due to him being ‘too tall’ for the description given to the women that had reported him.

“The decision was then made by the senior investigating office and his deputy to to exclude him as a subject in that enquiry,” Roger Boydell Smith who worked on the Bissett investigation told Netflix cameras.

“So basically nothing else was done, which baffles me to this day. Had Napper had attended the police station as he said he would, and his blood sample taken, he would have been arrested for the Green Chain Walk Rapes,” he continued.

Alex is now 36 years old (Image: Netflix)

“He didn’t, and it had catastrophic consequences,” he said.

Robert Napper's mother had also reported her son to the police, saying he had confessed to raping a woman, but it wasn’t followed up.

During the time of the Bissett murder investigations, detectives working on the case also called senior investigators of the Nickell murder, to discuss the similarities of the murders - and how they believe the same person could have committed both.

However, detective Roger Boydell Smith revealed that their thoughts were ‘dismissed’ as their ‘suspect’ Stagg was already in custody.

Stagg also appears on in the documentary, as he details how his false accusation 'ruined his life.'

The Murder of Rachel Nickell will be available for streaming on Netflix on June 4.

If you've been affected by any of the issues in this article, you can contact The National Sexual Assault Hotline on 800.656.HOPE (4673), available 24/7. Or you can chat online via online.rainn.org

A timeline of the murder of Rachel Nickell

November 1989

The mother of Robert Napper, from south-east London, contacts the police to say her son has told her he's raped a woman on Plumstead Common in London. However, police can't trace a rape and Napper is never questioned about this alleged crime.

March 1992

Two 17-year-old girls survive rape attempts within an eight-day period on Green Chain Walk in Hither Green, south-east London.

May 1992

A mother is raped on Green Chain Walk. Her child is with her throughout the ordeal.

July, 1992

23-year-old Rachel Nickell is stabbed 49 times on Wimbledon Common on 15 July. She is found dead with her distraught two-year-old son by her side.

September 1992

Colin Stagg, who lives near the common, is arrested on suspicion of murdering Nickell after Crimewatch callers report him looking like a photofit of the killer.

October 1992

Napper is eliminated from the Green Chain rape enquiry for being 'too tall'. Later in the month, he is arrested for possession of a firearm and ammunition, and is sentenced to eight weeks in prison.

August 1993

Stagg is formally charged with Nickell's murder.

November 1993

Samantha Bissett and her four-year-old daughter Jazmine are found assaulted and murdered at their home in Plumstead, south-east London, on 3 November.

May 1994

Napper's fingerprints are found at the scene of the Bissett murders, and a sneaker footprint matches his. He is arrested for their murders, and DNA tests identify him as the Green Chain rapist.

September 1994

The case against Stagg is thrown out by Mr Justice Ognall.

October 1995

Napper pleads guilty to the manslaughters of the Bissetts, two attempted rapes, and one rape on the Green Chain walk. He is sent to the notorious high-security psychiatric hospital Broadmoor, though he later denies going to Wimbledon Common when asked about Nickell's murder.

December 2007

After intensive private investigating, Napper is charged with Nickell's murder.

August 2008

Stagg is awarded £706,000 ($949,640) in compensation by the Home Office for being wrongly accused of Nickell's murder.

December 2008

Napper pleads guilty to manslaughter of Nickell on the grounds of diminished responsibility after being diagnosed with paranoid schizophrenia and Asperger's syndrome.