A former detective said he was in fear for his life when a masked raider pointed a shotgun at him and threatened to kill him during the robbery in which his partner Detective Garda Adrian Donohoe was shot dead.
Detective Garda Joe Ryan gave evidence at the Central Criminal Court of two armed men approaching the car he was sitting in with Det Gda Donohoe.
He heard a "loud bang" and a flash coming from a shotgun.
Aaron Brady (28) is charged with the capital murder of Det Gda Adrian Donohoe, who was then a member of An Garda Síochána acting in the course of his duty, at the Lordship Credit Union in Bellurgan, Co Louth, on January 25, 2013.
Mr Brady is also charged with the robbery of about €7,000 in cash and assorted cheques from Pat Bellew at the same location on the same date.
The accused, of New Road, Crossmaglen, Co Armagh, has pleaded not guilty to both charges.
Det Gda Ryan told the court how a person armed with a shotgun had said: "I'm going to f***ing kill you, I'm going to shoot you. Give us the money."
"I was in fear for my life," Det Gda Ryan said, adding the raider was also looking for the keys of the car.
He then noticed the two armed men run from his unmarked Garda Toyota Avensis and towards the exit of the car park, while a third raider jumped over a wall towards the vehicle blocking the exit, which drove off in the direction of Dundalk.
Det Gda Ryan said he drew his weapon and pointed it towards the car, and following a "quick assessment of the situation realised there was no threat to anybody's life" and decided not to discharge the firearm.
After this he saw Det Gda Donohoe lying on his back on the ground in a pool of blood with a wound to his face.
"I knew at that stage he was dead but I went for a pulse anyway," he said, adding there was "nothing that could be done for him".
The trial continues before Mr Justice Michael White.