Key dates in Rachel killing probe

The brutal killing of Rachel Nickell turned into one of the greatest unsolved cases of modern times.

* October 1989: Robert Napper's mother rings police to say he has told her he raped a woman on Plumstead Common in south east London. Police could not trace the rape and did not connect it to a rape at a house in the area.

* 15 July, 1992: Part-time model Rachel Nickell, 23, is found stabbed 49 times on Wimbledon Common in south west London. Her two-year-old son is distraught by her side.

* September 1992: Colin Stagg, who lived near the common, is arrested on suspicion of murdering Miss Nickell.

* 27 October, 1992: Napper is arrested for having a gun and ammunition and jailed until 18 December.

* August 1993: Mr Stagg is charged with murdering Miss Nickell.

* November 1993: Samantha Bissett, 28, is stabbed and mutilated along with her four-year-old daughter Jazmine at their home in Plumstead.

* May 1994: Napper, who lived nearby, is arrested for the Bissett killings. He is also charged with violent rape attacks on women.

* September 1994: Mr Stagg appears at the Old Bailey but the judge throws out the case because the police used an undercover policewoman to write to him to try to get him to confess.

* October 1995: Napper is sent to Broadmoor secure hospital for the Bissetts' manslaughter on the grounds of diminished responsibility.

* October 2001: The Nickell case is reviewed. Samples are examined using advanced DNA techniques not available when she was killed. Later, a second lab is brought in.

* July-September 2004: A match with Napper, a paranoid schizophrenic, is confirmed. Police set about building an unshakeable case.

* December 2007: Napper is charged with Miss Nickell's murder.

* August 2008: Mr Stagg is awarded £706,000 compensation by the Home Office for police blunders.

* 18 December: Napper, 42, pleads guilty to Miss Nickell's manslaughter on the grounds of his diminished responsibility.