By Danny Shaw
BBC Home Affairs correspondent
Kirk Reid subjected his victims to frightening attacks
The case of the serial sex attacker Kirk Reid, who police believe was responsible for at least 71 offences, has once again called into question the way police investigate sexual assault allegations.
Reid should have been arrested four years before he eventually was. If officers had been on their toes, they could even have pulled him in six years before his arrest.
The sorry saga began in August 2001 when an investigation was launched into an indecent assault in Battersea, in the London borough of Wandsworth.
Two weeks later, there was another attack in the same area. The perpetrator left traces of DNA and a profile was obtained, though it did not match any DNA records held on the national database.
Several more indecent assaults followed before an attack in December 2001 yielded the same DNA result as the first profile.
By September the following year, police had linked 26 sexual offences in Wandsworth. All were so-called "stranger" attacks on women walking alone, late at night.
The victims, who aged from their late teens to their early 60s, were usually on their way home, having taken the bus or Tube, or after being dropped off by taxi. The attacks were frightening. The women were approached from behind and forced to the ground.
It is arguable that even at this early stage, in 2002, Reid should have been on the police's radar.
He had been investigated and charged with an indecent assault seven years earlier and the records of the alleged offence would have remained on a police database, even though he was acquitted at trial.
But the first clear opportunity to arrest Reid occurred in December 2002, when he was stopped by police after a member of the public thought he was following a woman.
The case of John Worboys also raised questions about police failings
A police intelligence report was submitted, but Reid was not asked to give a DNA sample. Had he been, it would have matched the DNA recovered from two of the offences, and Reid would have been arrested.
As it was, the offending continued.
In 2004, police had two further opportunities to arrest Reid.
In January, officers received an emergency call about an assault in Soho, in central London. The offender was thought to be driving a red VW Golf. The registration number was given - it was Reid's car - but no one in the police followed it up.
In February, Reid was spoken to by a police officer after beeping his car-horn at a woman on the street. He was named as one of 11 potential suspects in the investigation into the assaults - but his DNA was never taken and he was not interviewed.
Once again, Reid had slipped the net, carrying out an estimated 20 further attacks until his eventual arrest in February 2008.
The arrest came about just five days after control of the investigation switched to Scotland Yard's Homicide and Serious Crime Command unit from the local "Sapphire" policing team, which specialises in sexual assault and rape investigations.
The Independent Police Complaints Commission (IPCC) will now examine why the Sapphire officers failed to detain Reid earlier.
According to Scotland Yard Commander Mark Simmons, who has responsibility for rape and sexual assault cases, this is at the "heart" of the issue.
Cdr Simmons said an internal Met review had uncovered "significant concerns with aspects of the history of the case".
The IPCC investigation is its third major inquiry into apparent failings made by Sapphire teams, who operate in all the London boroughs.
In March 2009, the IPCC announced it was to review the case of the taxi driver John Worboys, convicted of 19 offences including one rape and four sexual assaults on women.
Greater oversight by experienced senior officers should help detect future serial sex offenders far earlier
Worboys was arrested and investigated by police about a sexual assault in July 2007, but police never referred the case to the Crown Prosecution Service, and Worboys carried on offending for another six months.
The IPCC also revealed that four officers were to be disciplined over a separate case, dating back to February 2005, involving a botched investigation into a rape allegation - again, by the Met's Sapphire unit.
As a direct result of the Worboys and Reid cases, control of Sapphire inquiries is being transferred from borough-level to senior managers at New Scotland Yard.
Investigations will be conducted by specialist detectives, drawn from a dedicated team of 375 officers.
Scotland Yard says the new structure will be in place by the end of 2009. There is no guarantee that it will prevent future investigative blunders, but greater oversight by experienced senior officers should help detect future serial sex offenders far earlier.