The Police Ombudsman has confirmed that it is set to publish a major report into the loyalist murders of 19 people next month.
Operation Greenwich relates to a series of murders and attempted murders across several counties between 1988 and 1994.
The report includes details about the infamous 1993 ‘trick or treat’ murders of eight people in the Rising Sun Bar at Greysteel, Co Derry.
Collusion is suspected in some of the cases.
The publication of the report was one of several delayed in 2019 after "significant" new information was found on PSNI computers.
Former Police Ombudsman Michael Maguire later called for a review into how police disclose information.
There was controversy last month after it emerged that the publication of a separate report, Operation Achille, has been further delayed after issues were raised by the PSNI.
The majority of the Operation Greenwich murders are believed to have been carried out by the UDA/UFF.
It is understood that in a previous briefing to families it was confirmed that a significant number of documents have been viewed, including more than 2,000 intelligence reports.
It is understood that at the time investigators completed over 500 actions and more than 170 intelligence requests had been submitted.
It is believed that while some former police offices, including Special Branch members, co-operated with the investigation, others refused.
Mike Ritchie from Relatives for Justice welcomed news that the report is to be published.
"The families have been waiting for this report for a very long time," he said.
"The launch has been postponed many times so, although this is yet another delay, the promise of its release in January is a relief for the families."
A spokesman for the Police Ombudsman said: "Due to complexities associated with the ‘Maxwell’ process, the anticipated release of the public statement to the concerned parties will now be during the week commencing Monday, January 10, 2022."