Documents outlining the police's role in covering up the Hillsborough disaster were handed to the Crown Prosecution Service 14 years ago, it was claimed on Saturday.
Writing in The Independent, Alun Jones QC, who led a private prosecution for manslaughter on behalf of the families, said the Director of Public Prosecutions (DPP) needed to explain "why his office did absolutely nothing", even after being given detailed evidence that outlined the depth of the conspiracy.
Jones told the newspaper the Hillsborough Family Support Group launched the private prosecution of Chief Superintendent David Duckenfield and his deputy Bernard Murray - who were in charge when 96 Liverpool fans died on 15 April, 1989 - because of the DPP's failure to act.
Alun Jones QC said the DPP has serious questions to answer
Jones wrote: "We furnished the DPP, and Attorney General, with an analysis demonstrating the gravity of the conspiracy, but also proving that critical evidence of non-police witnesses had been withheld from the DPP and coroner in 1990.
"We showed how the tampering exercise was organised. I was clear that crimes of perverting the course of justice had been committed, but not by whom, and it was beyond the power of the families to investigate." The prosecution failed in 2000.
Jones also told paper that the police were "heavily protected" by law in investigations into their conduct, and that it took "herculean, demoralising efforts by the victims" before wrongs were brought to light.
The report revealed damning evidence of police tampering with evidence
A Crown Prosecution Service spokesman told the paper: "The Crown Prosecution Service was approached in 1998 by both parties to the private prosecution and asked to take it over.
"At the time we concluded we would not intervene and the private prosecution went ahead.
"We provided documentation to the Hillsborough Independent Panel about the reasons behind this decision in 1998 and the panel has made no criticism of the CPS or the DPP over this."