Police were "commended" for the use of informants to provide information which led to the recovery of a large number of the weapons. The ombudsman remarked: "It is unlikely these items would have been recovered if there had not been informers within the ranks of loyalist paramilitaries."
Many within the RUC and PSNI "worked tirelessly to bring those responsible to justice".
Police were aware of plans by the UVF, UDA and Ulster Resistance to import a significant consignment of weaponry to Northern Ireland in 1987 and knew about the arrival of the shipment shortly after it was landed.
Officers regained track of cars after losing them during a surveillance operation in January 1988 and a checkpoint on Mahon Road near Portadown, saw three men arrested and a substantial amount of the shipment recovered - the men were convicted of terrorism-related offences nine months later.
Local detectives investigated the seizure and "the majority of these officers acted as professionally as they could".
Without help from Special Branch and "through their own efforts", detectives deduced the weapons may have been retrieved from a farm and "set about trying to find it, but without success".
On February 4 and 5 police recovered a "significant number of firearms" at Flush Road in north Belfast believed to be part of the importation.
Upon the arrival of emergency services, including police, at the Heights Bar acted "quite correctly" - the preservation of life was prioritised over scene preservation and the initial police response to the murders "was appropriate and timely".
A major incident contingency plan, Operation Aristocrat, was quickly initiated, the crime scene was secured within 20 minutes of police arriving and a number of police and military vehicle check points directed.
Within 24 hours of the attack, Special Branch provided detectives with the names and details of people they believed responsible.
There was no evidence the security forces were aware the UVF were planning to mount an attack in Loughinisland.