Gardaí investigating the abduction of the Richardson family from Raheny, Dublin, on Sunday night and theft of €2 million from a Securicor van on Monday have insisted it is still too early in the investigation to focus on one gang.
Detectives are satisfied the Provisional IRA was not involved.
They strongly suspect the gang responsible had insider information. The vehicles used by the gang still had not been found last night, and there had been no arrests.
The events leading up to the robbery began on Sunday night when armed men arrived at the Richardson family home in Raheny. Marie Richardson and her two teenage sons were taken away from the house and held near Stepaside until Monday morning.
Marie's husband, Paul, a Securicor employee, was detained in his home overnight and forced to go to work as normal the next day.
The Securicor van on which he was working was robbed by the gang at a pub in the Strawberry Beds area of Dublin.
The officer leading the investigation, Assistant Commissioner Martin Callinan, confirmed that the notes stolen were not marked, making them untraceable. Senior Garda sources said the 100-strong investigation team was examining the possibility that any one of a small number of Dublin criminal gangs could have been behind the robbery.
However, they pointed out that the raid was almost identical to an incident in November 1999 when up to €1 million was taken during the robbery of a bureau de change in Dublin city centre.
The gang believed to be behind that raid were never charged, although some of them were arrested and questioned at the time.
These men, now in their late 40s and early 50s, are being "very closely looked at" as part of the current investigation. One is originally from Ballyfermot, another has a last known address in the south inner city, another is from the north inner city, while a fourth is originally from Northern Ireland.
In recent years one of these men was charged with murder, but the trial collapsed due to lack of evidence. Three of the four have been the subject of demands from the Criminal Assets Bureau of late.
One was ordered to pay €500,000 and another €250,000. A third man was forced to sell a house to pay the Cab. Gardaí have always believed that, through a romantic interest, the man forced to sell his house sourced the insider information which made the 1999 robbery possible.
During the robbery the gang of four called to the home of a couple in Booterstown, Dublin, just after 9pm one Friday night. When a resident opened the door gang members forced their way in and put a towel over his face and masks over their own faces.
They explained to the couple, Louise and Conleth Campbell, what was required of them and then sent them to bed for the night after threatening them with violence if they did not closely comply with their instructions.
The next morning Ms Campbell, who was five months pregnant with her first child, was driven to her place of work at a bureau de change in Nassau Street.
Ms Campbell had to deactivate alarms before opening the safe containing travellers' cheques, foreign currency and Irish punts.
The gang then tried to launder the money in Liverpool. It turned up in Birkenhead in February 2000.
