Mr Justice Frank Clarke completed his inquiries several weeks ago and is concluding a report that is expected to make recommendations about investigative procedures.
He opened his probe in June last year into the Garda Siochana Ombudsman Commission(GSOC) investigators after Sgt Mick Galvin took his own life at Ballyshannon garda station in May.
Sgt Galvin, 48-year-old father of three, didn't know he had been cleared of wrongdoing by a GSOC investigation.
GSOC officers had been questioning him about contact with a pedestrian, mother of three Sheena Stewart, 33, from Mountaintop, Letterkenny, shortly before she died in collision with a minibus in the early hours of January 1st in Ballyshannon town centre.
Sgt Galvin, a former manager of Sligo hurling and football teams, left a note addressed to his wife..
It was later found by his colleagues. He wrote that he could no longer take the pressure of an investigation by the GSOC, which had left him feeling like a criminal.
He wrote that he was innocent and he asked his loved ones to vindicate his good name after he was gone.
The Justice Department said today(Fri) that Mr Justice Clarke is in the process of writing his report, but it is not known at this stage when it will be presented to the Minister.
But sources involved in the inquiry said the judge indicated three weeks ago that he expected to be placing his report with the Minister "within weeks."