Andre Hanscombe is considering whether to bring a civil case against senior investigators identified as making a "catalogue of bad decisions and errors" by a police watchdog.
His solicitor Kate Maynard said Mr Hanscombe was also looking at whether to lobby Home Secretary Theresa May for a public inquiry that would have the power to summon the retired officers to give evidence.
She said Mr Hanscombe and the couple's son Alex wanted to do everything they could to hold those responsible for errors that led to the deaths of Miss Nickell, Samantha Bisset and her young daughter Jazmine, to account.
Mrs Maynard said: "There are three options left to him. Firstly, to do nothing, secondly, to press for a public inquiry which has the power to compel witnesses to attend.
"The third option might be to pursue civil proceedings, which of course has legal difficulties.
"He is digesting the report and considering whether he and Alex have done everything they need to do and can do to get justice for Rachel.
"He is considering his position, none of these options have been ruled out or ruled in."
A report published by the Independent Police Complaints Commission (IPCC) today said Metropolitan Police officers missed a series of opportunities to take Napper off the streets.
Officials said police blunders left Napper free to attack Miss Nickell, the Bissets and an unknown number of women who were raped and sexually assaulted as Napper stalked south London parks.
They also highlighted how police delayed bringing Napper to justice for Miss Nickell's death by falsely accusing Colin Stagg, despite mounting evidence he was not responsible.
The IPCC revealed how one police sergeant warned Napper was a serious threat to women as early as the mid-1980s after stopping him in the middle of the night and writing a lengthy intelligence report.
They said police ignored a telephone call from his mother in 1989 after she phoned her local station to report that he had confessed to raping a woman on Plumstead Common.
The IPCC revealed the suspicions of police were not aroused even after two people identified him as a suspect for a series of linked sex attacks on south London parkland known as the Green Chain.
He was visited twice by officers but failed to attend a police station to be interviewed or have his DNA taken before being mistakenly ruled out because he was seen as "too tall".
In a statement, Mr Hanscombe, who now lives on the Continent, welcomed the report and said the failures would have been buried had it not been for his determination to have them recognised officially.
He said police excuses and the lack of an explanation for why no-one will be held to account remain "unacceptable".
Mr Hanscombe said: "Nothing is going to bring Rachel, Samantha or Jazmine back.
"But having had some time to come to terms with this new reality, I now believe the best way to serve those who paid most heavily is to make sure all the lessons have been learned, to make sure that this could never happen again."
Miss Nickell was sexually assaulted and murdered in a frenzied knife attack on Wimbledon Common, in south London, as she walked with her toddler son on July 15 1992.
Scotland Yard spent years pursuing Colin Stagg for the murder, but an Old Bailey case was thrown out and the force eventually apologised to him and paid record compensation.
In early November 1993, Samantha and four-year-old Jazmine were killed in a violent knife attack at their home in Plumstead, south London.
In October 1995, Napper was convicted of killing the Bissets after his fingerprint was found at their home. He was detained indefinitely at Broadmoor for the deaths and several sex attacks.
He admitted killing Miss Nickell on the grounds of diminished responsibility at the Old Bailey in 2008 after forensic experts found his DNA on fibres taken from her body.
The National Police Improvement Agency (NPIA) is now conducting a "tactical debrief" of the investigation into the murder of Miss Nickell. It will be completed this summer.
The IPCC said no police officer would face disciplinary action because they have all retired, and one key senior detective had died. Criminal prosecutions were not considered.
Any civil proceedings would be expensive and fraught with technical legal difficulties. They may focus on individual misconduct or on the policies and procedures of the Met overall.
Rachel Cerfontyne, of the IPCC, said: "Without these errors, Robert Napper could have been off the streets before he killed Rachel Nickell and the Bissets, and before numerous women suffered violent sexual attacks at his hands."
Metropolitan Police Assistant Commissioner Cressida Dick, who is responsible for the force's specialist crime wing, will send a written apology to Mr Hanscombe and has offered to meet him.
A spokesman said: "The Met has accepted that more could, and should, have been done and had more been done we could have been in a better position to have prevented very serious attacks by Napper.
"We have made it clear to other victims and the family and friends of those who Napper attacked that we deeply regret the fact he was able to carry out these dreadful acts."
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