Senior gardai believe the gang which carried out the raid on a security van in Dalkey, Co Dublin, intended shooting to kill police officers or civilians who got in its way.
It emerged yesterday that one of the gang fired a shot apparently intending to kill the driver of a car which the raiders hijacked after their getaway car broke down.
The fact that the gang was armed with three AK47 assault rifles has also led senior gardai to believe that the raiders went with the intention of firing on gardai if confronted.
As it happened, two detectives, armed only with pistols, were within minutes of confronting the gang and would have been heavily outgunned.
There was no indication last night about the associations of the gang responsible but senior gardai believe they are almost certainly republican paramilitaries. They also believe the gang might have changed tactics after the last failed republican paramilitary cash-in-transit robbery in Co Wicklow, in May last year in which a "Real IRA" member, Ronan Mac Lochlainn, was shot dead in a confrontation with heavily armed gardai. Five other members of Mac Lochlainn's gang were arrested by armed gardai.
The Dalkey gang twice fired shots. One shot was fired into a rear tyre of the security van. Two shots were fired at the car which the gang hijacked after their getaway car broke down. One shot passed through the driver-side back window of the second car - a red Saab 900 - and the other passed over the roof. The driver of the Saab was very fortunate to suffer only a minor cut.
Gardai believe the fact that the gang had three assault rifles and were quick to use them was intended as a warning to i. them. They are concerned the gang will use the weapons again.
Yesterday, the senior detective investigating the Dalkey raid, Det Supt Martin Donnellan, appealed for information about the movements of a grey Ford Granada car which the gang had intended to escape in. The car, registration 89 D 30991, was bought from a man in Bray, Co Wicklow, on November 1st.
Det Supt Donnellan said gardai were anxious to talk to anyone who had seen the car since. The man who purchased it gave a false name and address. He was described as thin, of average height, with combed-back, mousey hair and prominent teeth.
The two other commercial vehicles used to block and ram the security van were stolen in the Rathmines area of Dublin in December and November.
All four vehicles were taken to Santry Garda station for detailed forensic examination yesterday morning. There gardai removed the 12 bags of cash, containing about £400,000.
Detectives working from Dun Laoghaire Garda station were also searching for witnesses of the gang's movements, either before the robbery or after they escaped in the hijacked Saab. The Saab was abandoned at St Paul's Church, Glenageary.