Four people are still in Garda custody tonight following the attempted robbery in Lusk, Co Dublin yesterday during which two raiders were shot dead by gardaí.
Three men and a woman are being held under the Offences Against the State Act at different Garda stations.A Garda spokesman said this morning they could be held for up to 72 hours without charge.
An internal Garda investigation is under way into the circumstances surrounding the shootings of Colm Griffin (33) and Eric Hopkins (24), both from Dublin's north inner city.
Amnesty International has called for an independent investigation into the shooting and said that in other jurisdictions any such events would be referred to an ombudsman's office, which this State still does not have.
Griffin was a known drug dealer and armed robber while Hopkins was also known to gardaí. Garda sources say the men were fired on after they failed to drop their weapons despite repeated requests to do so.
Post mortems carried out on the bodies last night show the men died after being shot in the front upper body.
In a statement yesterday, gardaí said they were conducting an operation in the area at the time of the attempted armed robbery.
They said they had received information that a robbery on the post office might be imminent and members of the ERU, the Emergency Response Unit, and local gardaí from the Meath-Louth division were waiting on the gang when they arrived at about 8am.
Meanwhile, Eugene Larkin, who owns the shop adjoining the post office, expressed concern that his staff and customers were put in danger and that gardai did not inform him that they were carrying out the operation.
He said there were about four customers in the shop at the time and that there was shooting inside the shop. His manager had been confronted by armed and masked men shortly after she arrived at the shop. A gun had been put into her face and she had been ordered to "hit the ground". The events became "a blur" to the four deli staff after the point where they were threatened by the raiders. "It was all over in about 30 seconds," Mr Larkin said.
"My concerns are that my staff were left there. The guards knew about this operation, this robbery was taking place. They had armed guards in the post office with the post office staff but yet left my staff unprotected in the shop and the customers as well. And I'm just not very happy with it. I'm not happy with the answers I got from the guards when I finally spoke to them at about 5 o'clock yesterday evening."
Mr Larkin claimed the post office knew about the Garda operation but that his staff had not been told.
Speaking on RTE's Morning Irelandprogramme, he said that if the gardai knew in advance about the robbery, they should never have allowed the gang to enter the shop.
His staff were very annoyed to learn last night that the gardai were in with post office staff and had known about the operation. It had increased the trauma for them that they had been "left exposed".
"They are very upset because they were lying on the ground and the people that were shot fell just feet from them. They were observing all this from the ground. I don't think it's right. If the guards knew that this operation, this robbery was going down, I think they should have had staff out there and maybe armed guards in posing as staff members. I'm just not happy."
Mr Larkin said he eventually got to speak to a senior garda at about 5pm and he had made his unease "very clear".