The DUP is defending the senior police officers who refused to co-operate with the Police Ombudsman's inquiry into collusion between the RUC and loyalist paramilitaries.
Nuala O'Loan revealed earlier this week that several senior officers had failed to co-operate with her investigation, which found that RUC Special Branch officers protected loyalist murderers from prosecution.
The DUP's Ian Paisley Jnr claims they were within their rights to withhold co-operation because Ms O'Loan was engaged in a "fishing exercise" without any hard evidence of collusion.
He has also rejected suggestions that they had moral obligation to co-operate, saying: "At the end of the day, it boils down to what is your legal right."
Meanwhile, the two main unionist parties in Northern Ireland have blocked an attempt to have the Ombudsman's report debated in the Stormont Assembly on Monday.
Sinn Fein and the SDLP, who proposed the debate, have condemned the failure of the DUP and UUP to support the move.
Sinn Fein says they have shown "breath-taking hypocrisy and cowardice" , while the SDLP says they have "failed the first test of operating a democratic parliament".
A UUP spokesman claimed the debate would have been bad-termpered and would have only served to give nationalists a chance to grand-stand.