Scotland Yard is braced for the findings of an independent inquiry into the murder of Rachel Nickell.
The London force is expected to face a huge compensation bill for blunders that led to her death on Wimbledon Common in July 1992.
Miss Nickell, 23, was stabbed to death and sexually assaulted in front of her young son by psychopathic rapist Robert Napper.
Her partner Andre Hanscombe complained to the Independent Police Complaints Commission (IPCC) after Napper was jailed indefinitely in November 2008.
Officials at the IPCC will publish the findings of their inquiry that focused on claims that Met officers could have done more to stop Napper during a five-year series of up to 86 sex attacks.
Critics said Napper could have been stopped in 1989 after his mother reported he had confessed to rape. Police could not trace the crime and did not interview him or collect his DNA. Napper's DNA was again not taken when he was questioned about at least four other rapes a few months later.
It was also alleged that detectives should have linked him to sex crimes before he slaughtered Samantha Bisset and her four-year-old daughter Jazmine in 1993.
Kate Maynard, Mr Hanscombe's solicitor, said he wants someone to be held accountable for the "police failings" and delay in establishing Napper's guilt. She said: "All possible avenues will be explored for bringing the police to account for their many failings."
Mr Hanscombe is seeking compensation on behalf of himself and his son Alex, who is now in his early 20s.
Former prime suspect Colin Stagg received £706,000 compensation from the Home Office after being wrongly accused of Miss Nickell's murder. He was cleared in 1994 after a year in jail awaiting trial, but remained a social pariah for another decade as police were convinced he was the killer
