The officer in charge of the Garda operation at the post office in Lusk said the objective was to stop the raiders getting into the post office, arrest them and recover the firearm.
Colm Griffin and Eric Hopkins were both shot dead during a botched robbery at Lusk post office in Co Dublin.
Detective Superintendent Dominic Hayes told the inquest into the deaths of the two men that gardaí believed the gang were working on inside information gleaned from a family member with a close connection to an employee of the Village Store and post office.
He also said that the gang had access to three stolen vehicles in Lusk that day and that two other people were also involved and arrested.
Mr Hayes said Garda intelligence indicated that the firearm was only to be delivered immediately prior to the raid and that the raiders would be going into the front door of the shop.
Mr Hayes also said that when Mr Griffin was spotted earlier with the other gang members it had not been established that any criminal act had been committed. He added that when the gang arrived at the post office in a stolen black Skoda there was no confirmation that they were three raiders that were going to rob the post office.
He said he did not know that Mr Griffin and the others had transferred from a white van to a black Skoda.
The decision was made to intercept the car when it arrived at the post office, but by the time the members of the Emergency Response Unit reached it the raiders had already gone inside.
In testimony earlier today, two detectives from the Emergency Response Unit said that the raiders did not come into the area for which they had responsibility for.
A member of the National Surveillance Unit has told the Coroner's Court that he kicked a pistol away from an armed raider after he had been shot dead.
Detective Garda B said he was a member of the National Surveillance Unit and was dressed as a builder in the shop.
He said he was there to protect the staff and customers in the shop and that if the gardaí had challenged the raiders outside the post office his job was to stop customers leaving and walking into danger.
He said he was in the post office when the raiders arrived and began hammering with a sledge hammer at the hatch. He said his initial reaction was that the bangs sounded like gunshots so he told the staff to move back and get down.
He said he drew his revolver and followed Det Garda A - a member of the Emergency Response Unit - out into the shop to confront the armed men. He said he believed his own life and the life of the staff and customers were now in danger because a secure area had been breached.
He also said that he saw the two raiders after they had been shot and that he pointed his gun at the third raider, Gavin Farrelly. He told him to put down the sledge hammer and get on the ground and Farrelly complied. He said he was concerned that he might have a firearm and kept him covered while kicking the gun away from Mr Griffin.
The inquest continues.
