Gardai are reportedly investigating a location in Co Meath where they think the family of a bank official were held captive during a robbery at the Bank of Ireland in Balbriggan.
Five men and two women remain in custody connection with yesterday's abduction and the subsequent robbery of up to €550,000 from the bank.
The arrests follow major Garda activity in adjoining areas of north Co Dublin, south Co Louth and east Co Meath during and after the "tiger" kidnapping.
Four men were arrested during a Garda operation in Ballymun last night and held under Section 30 of the Offences Against the State Act. It is believed they were all detained at a hotel in the area at about 1am and taken to Lucan, Ronanstown, Kilmainaham and Kevin Street Garda Stations.
They are aged 27, 30 and two of them are 41, according to a Garda spokesman.
A woman (36) arrested in Drogheda yesterday remains in custody in Drogheda Garda station. A man (20) arrested in Raheny is being questioned in Raheny Garda Station, and gardaí in Balbriggan are questioning a woman in her 20s who was held in the north Co Dublin town yesterday.
Speaking at a graduation ceremony in Templemore, Garda Commissioner Noel Conroy said: "Our main focus from the time we received the report was the security of the individual and the health and welfare of the individuals taken," Mr Conroy said at a garda graduation ceremony in Templemore."
Garda Commissioner Noel Conroy
"The arrests are very significant in so far that it is clear now that we know exactly the number of people involved, and of course we will be dealing with other issues in relation to previous crimes."
Mr Conroy paid tribute to the bank for co-operating with gardai. "I want to express my thanks in particular to those that actually made sure the protocol that we entered into with the various agencies have been complied with," he continued.
"Where that happens you will find we will have good results. "The health and welfare of the individual is paramount in every single situation and that's the way we work."
Mr Conroy said tiger kidnappings could be looked upon as an easy way of getting money, and raised concerns that people who steal money in crimes like this will use it to commit further crimes, like the purchasing and trafficking of drugs.
"It is important for us that this type of crime is not allowed to go on and on," he added.
"It started really in Northern Ireland and it soon came across into our jurisdiction and I'm glad now that things are beginning to change. I am sure that in time you'll see people being brought before the court."
A Garda spokeswoman said those incustody could be held for a maximum of 72 hours.
A man (18) and a woman (23) arrested in Julianstown, Co Meath, yesterday afternoon and held in Santry and Coolock Garda stations have released without charge.
Gardaí are believed to be investigating links between yesterday's robbery and other recent kidnappings of bank officials.
The crime began at 8.30pm on Wednesday when the assistant manager of Balbriggan Bank of Ireland along with his wife and two sons - aged 17 and 23 - were held hostage in their Swords home by an armed gang.
At about midnight, the official's wife and children were taken from the house and brought to a mobile home on the outskirts of Drogheda, Co Louth, where they were held overnight.
The official was made to go to work as normal yesterday morning where he withdrew the cash. The cash was later dropped off between Donabate and Swords at the Malahide estuary - some time between 11.30am and midday and later taken by members of the gang.
At about the same time the money was dropped off, the man's wife and sons were taken from where they were being held and left in a car at the side of Slane Road, at Oldbridge, just outside Drogheda, Co Louth, close to the M1 motorway.
A major Garda operation, including specialist armed units and gardaí from the Dublin metropolitan area, was put in place as the events unfolded.
The Garda helicopter was involved, but gardaí believe that up to six vehicles and 10 people involved in the robbery may have dispersed over a wide area before gardaí felt it was safe to put their operation into action.
Several checkpoints were set up, and it was at one of these - in Julianstown Road, Co Meath - that officers stopped a car and arrested its two occupants.
These were the first out of a total of nine arrests in relation to the incident.
The cash has not yet been recovered.
Addtional reporting PA