The PSNI Historical Enquiries Team is behind the US court battle over terrorist testimonies held by Boston College, it has emerged.
The wrangle originates in a HET investigation into the 1972 IRA murder of mother-of-10 Jean McConville.
A PSNI spokesman rejected claims that the US court case had been started by a small group of detectives or that it had a political agenda.
"This was a corporate decision," he said.
"This investigation was referred by the Historical Enquiries Team in line with agreed protocols about legacy investigations in which current lines of inquiry have been identified.
"It is now being conducted by detectives in serious crime branch who have the skills, the experience and the resources to progress the investigation with full corporate approval," he added.
Boston College holds an archive called the Belfast Project in which former terrorists spoke frankly about their careers on condition that nothing would be revealed in their lifetimes.
The first to die was Brendan Hughes, a Belfast IRA leader, who gave alleged details of Mrs McConville's abduction.
Dolours Price, another former IRA member, then let it be known that she had given interviews to the project and that she had knowledge of Mrs McConville's murder.
The PSNI has now applied, under a 1994 Mutual Assistance Treaty between the UK and US, for all material in the archive bearing on the case to be released to it.
As a result, all the papers have been handed over to a US judge, William Young.
He is considering an application from Ed Moloney and Dr Anthony McIntyre, who worked on the project, to halt the process and not pass the documents on. They argue that the disclosure could derail the peace process.
However, legal experts believe he will hand over all relevant material in a few weeks' time.
Last month the judge said that, given that the criminal allegations at issue include kidnapping, false imprisonment and murder, "they weigh strongly in favour of disclosing the confidential information".
Professor Jim Cohen, a criminal law expert at Fordham University in New York, said he believed the Justice Department would consult with the State Department, which handles foreign policy, before reaching a decision.
"If I were a judge, I'd want to know what the hell the State Department had to say about this," he said.
If reports of the contents of the archive are correct then Gerry Adams, who has always denied any involvement in the McConville case, could face police questioning.
However the testimony of Ms Price and Mr Hughes is not sworn so a conviction is unlikely.