Former senior police officers are weighing up how they can fight back against Police Ombudsman Nuala O'Loan's hard-hitting report.
Some retired Special Branch officers say they have been treated unfairly by the Ombudsman's methods in investigating informer Mark Haddock's role in murders.
The officers are reluctant to respond publicly to criticisms in Mrs O'Loan's report, but told the Belfast Telegraph that they may come forward at a later date.
They say they are also considering court action, although that may be difficult - Ombudsman reports carry parliamentary protection.
Their views were echoed last night in a statement by solicitors for the group known as the Northern Ireland Retired Police Officers' Association.
The statement called for the report to be reviewed by "an independent and competent authority whose conclusions will be wholly evidence-based and devoid of emotive language or melodramatic import".
However, the Ombudsman's report noted that the investigation had been reviewed by a former chief superintendent from England, who described the investigation's analysis as "outstanding" and said there was nothing to indicate the investigation was managed "other than professionally and well".
In their statement, the retired officers said: "We again strenuously reject any knowledge of wrongdoing and would remind the public that the PPS has already directed 'no prosecution' against any serving or former police officer, a key point seemingly being overlooked in the commentaries offered to date.
"Representations have been made without adequate response to the Secretary of State, the Lord Chancellor, the Criminal Justice Inspectorate and the Cabinet Office."
In her report, Mrs O'Loan was critical of some unnamed retired officers, saying they were the "main difficulty" in compiling her report. She said she was "particularly concerned" that senior officers " who had significant responsibilities within Special Branch" had refused to cooperate with her investigation.
Several officers say Mrs O'Loan wrote to them at an early stage in her investigation asking them to discuss the case informally and eventually reach an "agreed statement" about it. But they say they were not offered the opportunity to respond to specific criticisms in her report.
They also indicated that they refused to cooperate with her office because they continue to believe that the Ombudsman's report on the Omagh bombing investigation was flawed.
In the statement issued by the retired officers' solicitors, they said some officers "but not all, were invited to have an informal talk at the early stages of the inquiry, as the report states 'simply being asked to provide an explanation of Special Branch and CID internal practices during this period'."
The officers said they were cautious about the informal nature, but wrote back to offer assistance about where some material might be found.
"Thereafter, we held ourselves available for further interview," they said.
They said they expected that the "next point of contact would be in relation to incident specific matters where detailed explanation would be sought from each officer as to the manner in which his duties were discharged and practices and policy applied".
But they said that contact never came.
A spokesman for the Police Ombudsman said retired officers were given opportunities to help the investigation. He said that every piece of evidence had been properly sourced.