The cold-blooded killers of Detective Garda Adrian Donohoe hid behind walls before entrapping the officer and his partner, it has now emerged.
The armed gang who lay in wait deliberately murdered Mr Donohoe as another of their members blocked the exit from the credit union car park where the officers were trapped.
Mr Donohoe was blasted with a shotgun at close range after the men leapt out when he approached to investigate.
The details of the killer trap can be revealed as senior Garda officers say they are confident that the getaway car, found burnt out at Fews Forest near Keady in south Armagh, will yield vital clues to the identity of the gang.
The car, a VW Passat, has now been identified as the getaway vehicle and officers will use vital details such as the chassis number to trace its history.
Irish Justice Minister Alan Shatter said it is probable that the car was used by the killers.
Fresh details have now emerged of the trap Mr Donohoe was lured into, with three of the four raiders hiding behind walls of the car park at the credit union premises.
Two credit union officials had agreed to rendezvous there to bring their cash to a bank night safe in the town.
One of the officials was carrying the €4,000 (£3,432) lodgment from the Lordship premises.
The second official had collected up to €30,000 (£25,717) from three other credit union branches in the Cooley area.
The officials, a man and a woman, got into their cars and intended to travel in convoy to the bank with the Garda escort car.
But one member of the gang suddenly blocked the exit with the Passat and Det Garda Donohoe was investigating the situation when he was shot in the head.
Then the raiders snatched the bag containing the €4,000 and sped away.