MORE than 3,600 "structured" lines of inquiry are being pursued by the gardai and the PSNI as they hunt down the killers of Det Garda Adrian Donohoe.
The officer was shot dead in January as he escorted the collection of cash from the Lordship credit union outside Dundalk, Co Louth.
Gardai believe they know the identity of most of the cross-border gang who gunned him down in cold blood, but they are still gathering evidence.
Garda Commissioner Martin Callinan said: "This is a huge, huge investigation. We have collected over 3,200 statements and reports and gathered more than a thousand exhibits.
"We are currently working our way through all of the outstanding lines of inquiry until the process has been completed and we are focusing on a particular direction."
Mr Callinan added: "We want to ensure that we will be ready, if and when an opportunity presents itself, to bring these people to justice."
PSNI chief constable Matt Baggott rejected any suggestion that his personnel would not go into south Armagh to follow up inquiries there.
He added: "We will pursue every avenue and spare no resources. That is our commitment to the Garda Siochana and we will support them fully."
Mr Callinan praised the PSNI for its co-operation in the Donohoe operation and in other inquiries.
He said Tuesday's seizure of over nine million cigarettes, with a value of over €4m, was an example of the level of co-operation between the forces
The two police chiefs were speaking in Dundalk at the start of a two-day police conference on organised crime with tentacles in both jurisdictions.
This year's seminar is focusing on policing challenges beyond traditional geographic borders and the co-operation that exist to tackle gangs involved in fuel laundering and cigarette smuggling and other serious crime is now being extended to include cyber offences. For the first time, however, the two ministers for justice did not attend.