By focusing on Colin Stagg, the police miss vital clues. In the summer of 1989, there was a brutal rape in Plumstead, South East London. A woman was getting her children ready for school with the back door left open. She turns around after drying her hair to see the offender with a knife threatening her and her kids if she didn’t comply. It was the first of many such attacks by the same man over the next four years.
Unbelievably, in August that year, the rapist, Robert Napper confesses all to his mother. She believes him and rings the police. But her call and the crime are tragically not matched.
Robert Clive Napper is one of a very unusual and mercifully small group of sexually sadistic serial killers. His mother was concerned about him from the start and sent him for assessment. He returned and said,
‘The psychiatrist thinks I’m mad.’
There’s some suggestion that Robert was abused as a child by someone quite close. (One report alleges he was raped, tellingly, during the day, in the woods near his home.) He also suffers from Asperger’s Syndrome and grows up increasingly isolated, though he does manage to secure work as a warehouseman at the Ministry of Defence.
After his first attack on a woman, he often hunts around the Green Chain Walk, a string of leafy pathways linking a lot of South East London. Just weeks before he kills Nickell, he attacks a woman with a child. He jumps out, pushes her to the ground and strangles her as he rapes her in front of her child. The similarities between this and the Nickell murder are obvious, but they’re not connected. Napper’s psychosis means he believes he’s untouchable. Police mistakes mean that for too long a time, this will be the case.
When the police release a photofit of the Green Chain rapist, two sets of neighbours positively identify him. On both occasions, he doesn’t turn up at the police station to give blood samples. Incredibly, he’s never pursued.

16 months after Nickell’s murder, in November 1993, London is shocked by another vicious killing.
Samantha Bisset had adopted the ‘New Age Traveller’ lifestyle in her youth, but had since become a very focused caring mother. Her four year old, Jazmine, melts everyone’s hearts.
Napper stalks them both. Samantha doesn’t have curtains in her basement flat and has no problem with walking around inside naked. When she thinks she sees a man at the window, her attitude changes. It’s too late.
She tries to resist Napper as he enters her home but just one of the knife wounds severs her spinal cord.
Samantha’s boyfriend is the first to discover the aftermath. He sees a stain on the carpet. Elsewhere, it’s carpeted with clothes. Under some of them, is Samantha. Her body has been cut open from her chest to her genitals. Her rib cage has been pulled back to expose her internal organs, and each one has been stabbed. Someone has attempted to slice off her leg and a piece of her abdomen has been taken as a trophy.
The boyfriend enters Jazmine’s room hoping she’s survived. But she too is covered. The murdered four year old has also been raped.
A police photographer who later records these scenes is unable to ever work again.
Detective Superintendent Micky Banks leads ‘The Plumstead Ripper’ investigation. And he links it with ‘The Green Chain Rapist’ and the Rachel Nickell murder. Unbelievably, the profiler Paul Britton is on all three cases, but he fails to make this connection. And the Green Chain investigators have already discounted Napper because, at 6ft 2in, he’s too tall for their suspect, and the Nickell squad are convinced that Colin Stagg is their man.
Forensics find Napper’s fingerprints at the Bissett murder scene. Napper’s fingerprints are on record from eight previous police meetings. One, in 1992, saw him arrested for stalking a civilian police employee who lived in Plumstead. At Napper’s flat, they find a book of maps of the London area with several markings around Plumstead and comments about how women should be wrapped in cling film and be abused. They don’t make any links.
The Bissett detectives do and place Napper under surveillance on 20 May 1994. They arrest and interview him. Napper remains stone cold calm throughout. A knife found on the Common the previous August, is matched to Napper. But despite a knife with his fingerprints being found on his raping grounds, no connection is made to the Nickell case, and the possibility that Colin Stagg is innocent.