The Guerin report found that An Garda Síochána cooperated fully with the review.
Sean Guerin SC reported: "I am satisfied that diligent and thorough efforts were made to locate all relevant documentation and that An Garda Síochána cooperated fully with the review."
He wrote that he initially received to archive boxes of documentation on 11 March, and received substantially more during the course of his investigation on the foot of specific requests, totalling more than a dozen archive boxes.
"Assembling all of that material and furnishing it in time required a significant effort on the part of the Chief Superintendent [and other Gardaí], and it was their efforts that delivered the vast majority of the documents relevant to this review," he wrote.
Mr Guerin added that he had received similar cooperation from the Department of Justice and from the office of the Director of Public Prosecutions.
However, he said such cooperation was not forthcoming from the Garda Ombudsman's office (GSOC).
Despite being told by GSOC that the required documents were being located and collected as a priority, Mr Guerin never received what GSOC described as a "voluminous' collection of documents.
"I do not understand why the obstacles to my seeing (the documents) were first identified to me in correspondence delivered shortly before the close of business on the eve of the date upon which the report was due," he writes.