SLAIN detective Adrian Donohoe knew his killer, gardai believe.
OFFICERS now have a "very strong idea" who actually fired the fatal shots to the head of Det Gda Donohoe.
The murdered officer questioned the suspect a number of times about serious crimes.
"The sick thing is that this brute would have known Adrian personally," a source told the Herald.
"Gardai have a very good idea where they are going with this investigation and you can expect arrests over the coming days. Anyone with any information should make themselves available now. "
Thousands of mourners, including President Michael D Higgins and the Taoiseach, today attended the funeral of Det Gda Donohoe who was laid to rest five days after the brutal killing.
The chief suspect for the murder is based in south Armagh and has strong connections to the Dundalk area.
He is suspected of organising and participating in a raid on the Lordship Credit Union in 2011 during which two gangsters escaped with €62,000.
Sources say gardai are confident that he is not in this jurisdiction at the moment.
Among the other crimes of which his mob is suspected is a raid in Crossmaglen, Co Armagh, in January 2010.
In that raid a stolen digger was used to steal an ATM from a Bank of Ireland branch.
The ATM was just 100 yards from a local PSNI station.
The mob are also suspected of targeting ATMs in Co Cavan, Co Monaghan, Co Armagh and Co Fermanagh and have been on the radar of the garda's Organised Crime Unit.
Two brothers from Coolock, north Dublin, nicknamed ‘The Taliban’, are still in the frame for being part of the gang involved in Friday night's murder.
The brothers have been linked to a spate of gangland murders in Dublin and Co Louth and have been based in Newry, Co Down, in recent times.
The Irish League of Credit Unions has offered a €50,000 reward.
A spokesperson said: “We have been inundated with calls from credit unions who have been offering support to our colleagues in Lordship Credit Union and to the gardai. We offered this as a way of helping the gardai solve this case.”
Gardai have established that the Volkswagen Passat used in the raid was stolen in
Clogherhead area of Co Louth between 11.30pm and 4.30am on the Tuesday night.
Wednesday morning before the murder. After Det Gda Donohoe's murder, the car was driven across the border. It was set on fire near Darkley, south Armagh, where it was discovered by the PSNI on Sunday morning.