The Metropolitan police issued a series of apologies today over their gross mishandling of the Rachel Nickell murder inquiry. Officers missed several chances to apprehend Robert Napper who sexually assaulted or raped as many as 86 women and murdered three people in the five years after his mother warned detectives that he may be a rapist.

Detectives passed up the chance to take a DNA sample from Napper, ignored people who recognised him in a photo-fit and released him after he was questioned as a "peeping tom".

Police now admit that Colin Stagg, the man charged with her murder after a "honey trap", was completely innocent. They also concede that they should not have relied so heavily on the advice of a forensic psychologist during the investigation and should have caught Napper before he murdered Samantha and Jazmine Bissett.

August 1989: woman raped in her home in Plumstead in front of her two children; believed to be the first of Napper's sex attacks.

November 1989: Napper's mother tells police her son has claimed to be a rapist but officers find no record of the crime.

March 1992: two women raped close to Green Chain walk in south-east London.

May 1992: young mother raped as she walks with her daughter in a buggy in south-east London.

July 1992: Rachel Nickell murdered as she walks on Wimbledon Common, south-west London, with her two-year-old son Alex. The killer stabbed her 49 times and mutilated her body in a frenzied attack.

August 1992: Robert Napper is questioned about the Green Chain rapes after callers tell police he looks like a photo-fit of the suspect. Napper is asked to give a DNA sample but does not turn up for appointments. Later dismissed as a suspect because he is too tall.

September 1992: Colin Stagg arrested as a suspect for the Nickell murder. He is questioned then released.

October 1992: Napper is arrested after weapons found in his flat; pleads guilty and is jailed for eight weeks.

January 1993: Police begin "honeytrap" operation designed to get Stagg to confess to an undercover policewoman, Lizzie James, who begins writing sexually explicit letters to the suspect. Dr Paul Britton, a forensic psychologist who inspired the television character Cracker, was appointed as a close adviser to the police team.

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