A 42-year-old man has admitted to killing and sexually assaulting 23-year-old mum Rachel Nickell whilst she was out walking with her toddler son on Wimbledon Common more than 16 years ago.

Robert Clive Napper, pleaded guilty to manslaughter on grounds of diminished responsibility of Rachel on Wimbledon Common on the 15th July 1992 at the Old Bailey. He was sentenced to a hospital order for the rest of his life.

The body of Rachel Nickell was discovered by members of the public on the Common. Her two-year-old son was found crying next to her.

Rachel had been the victim of a violent sexual assault and murder in which she received 49 stab wounds.

Charged last year - confessed other killing

On 28 November last year Napper was charged with Rachel's murder. He was already a patient at Broadmoor high-security psychiatric hospital having pleaded guilty on grounds of diminished responsibility to the manslaughter of Samantha Bisset, 28, and her daughter Jazmine Bisset, 4,in 1993 in Heathfield Terrace, Greenwich

Napper was also convicted of one rape and two attempted rapes which happened in 1992. These sexual assault offences formed part of Operation Ecclestone which was a series of linked sex attacks in south-east London.

The investigation into Rachel's murder was taken on by the Murder Review group in October 2001.

DNA - red paint flicks

Napper was identified by the re-investigation team through a mixed DNA profile in July 2004 as a result the investigation was allocated a full murder team once more.

Further evidence was uncovered including red paint flecks, found in her son's hair, which appeared to match and crucially further DNA profiling work carried out in 2007  showed Napper was almost certainly the killer.

Since Rachel was murdered the investigations have handled 9,292 messages received, generated 12,821 lines of inquiry and considered 10,810 documents. More than 4,500 statements have been taken and 6,061 men considered for elimination. 34 people were arrested during the inquiries.

Assistant Commissioner John Yates issued a statement apologising for mistakes made in original investigation:

"On 15 July 1992, over 16 years ago, Rachel Nickell was murdered on Wimbledon Common. It was a sickening and violent attack on a young mother out walking with her 2-year-old son. It was a case that shocked the nation and one that has remained in the public conscience ever since.

We in the Met Police began a major re-investigation into her murder in 2001. Today, Robert Napper has finally admitted his responsibility for killing her.

At last, we can finally say that we have achieved justice for Rachel and her family. It is quite impossible to imagine the grief and the pain that they have experienced over the past 16 years. This will always remain with them but it is to be hoped the knowledge that her killer is behind bars will bring them some degree of comfort.

Turning now to Mr Colin Stagg. The Metropolitan Police would have liked to have provided some clarity about his status in this inquiry at a much earlier stage. It is a matter of regret that the rules governing disclosure governing criminal trials have, throughout the past seven years, prevented us from publicly acknowledging the mistakes that were made in how this case was originally dealt with in the early 1990s.

In acknowledging these mistakes, I need to and must set the record straight with regard to Colin Stagg.

In August 1993, he was wrongly accused of Rachel's murder. It is clear that he is completely innocent of any involvement in that case. I today apologise to him for the mistakes that were made in the early 1990s and we also recognise the huge and lasting impact that this has had on his life and on behalf of the Metropolitan Police today I have sent him a full written apology.

We also acknowledge there are other cases where more could and should have been done. Had more been done, we would have been in a position to have prevented this and other very serious attacks by Napper. I particularly here refer to the dreadful murders of Samantha and Jasmine Bissett in November 1993.

I do say though the way in which murder is investigated now has changed significantly from 16 years ago. Improvements in forensic techniques, particularly scientific developments around DNA, new rules governing disclosure, improved training, and our close and statutory relationship with the CPS, all mean that the chances of such potential miscarriages of justice as in the Colin Stagg case happening again are very small.

However, we must not be complacent and cases such as this serve to remind us of our duty to protect the innocent and to ensure that evidence is properly gathered and presented against the guilty.

It is also now and lastly proper to recognise the dedicated and professional work of the current investigation team that has brought us to this point. They have been unstinting in their attention to detail and their determination over a number of years to find the evidence that has brought Robert Napper to justice. In spite of the flaws in the first investigation, it is clear that we have never given up in our determination to bring this case to its proper close." 

Click on 'photos' to see the scene and the toolbox that linked Napper to the killing