Sex attacker is prime suspect in Nickell case

Twelve years after Rachel Nickell was stabbed to death in front of her young son, detectives are said to be "increasingly confident" that they will bring her killer to justice.

Scotland Yard sources confirmed last night that a convicted sex attacker had emerged as a prime suspect. Advances in forensic science since the young mother was repeatedly stabbed on Wimbledon Common in 1992 have offered renewed hope that one of the most infamous cases of recent times may be solved.

Detectives from the Murder Review Group reopened the investigation on the 10th anniversary of her killing. Last year they revealed that an "exciting development", involving the retrieval of a DNA sample from the 23-year-old's underwear, could prove a vital breakthrough.

While the finding was only a partial sample, scientists were hoping to enhance it so that it could be compared to that of known offenders. Last night, a source said that detectives were increasingly confident about catching the killer. While the new investigation was still in its early stages, he said they had seen some success.

Ms Nickell and her two-year-old son, Alex, were walking their dog on the common on 15 July 1992 when she was stabbed 49 times and her throat was cut. Alex was found clinging to her body, begging her to "get up".

Colin Stagg was arrested and charged. But he was cleared at his trial, after a year behind bars, when it emerged that an undercover policewoman had been used as bait to try to persuade him to confess.

The man now regarded as the a prime suspect is a paranoid schizophrenic, held at Broadmoor high-security hospital, who raped and killed a young mother before sexually abusing and smothering her four-year-old daughter. He pleaded guilty to manslaughter on the grounds of diminished responsibility.

His attacks, 16 months after the Wimbledon Common killing, bore a similarity to Ms Nickell's murder. His name was first raised as a possible suspect as far back as 1995 but nothing was found to link him to the crime.