A GARDA is being questioned about the theft of €9,000, which was being held in storage at a garda station.
The suspect, who is a rank and file member of the force and in his 30s, was arrested by officers at his home yesterday morning.
The sum of money was taken from Balbriggan garda station in north county Dublin.
The arrested man was being held last night at Irishtown station in the south city under section 4 of the Criminal Justice Act and can be detained without charge for up to 24 hours, excluding rest periods.
Last month, the Irish Independent disclosed that the missing money was suspected to be part of a €26,000 haul taken in a robbery from the post office at Lusk, Co Dublin, last January.
The money went missing from an evidence bag while it was being held in a strongroom at Balbriggan station.
Garda Commissioner Martin Callinan had indicated that investigators were making good progress with their inquiries and they were satisfied after an extensive search of the station that the money had not been mislaid.
The haul was initially checked and then photographed, fingerprinted and forensically examined before it was bagged and tagged as potential evidence.
The evidence bag was then placed in a safe in a strongroom at Balbriggan station.
The discrepancy in the amount of money in the safe was discovered in February when John Wilson, the owner of the Costcutter shop where the post office is located, called to the station to seek the return of the cash.
Officers found a small tear in the bag and when they checked the contents they discovered there was only €17,000 still held in the safe.
An investigation team interviewed all gardai, who might have been in contact with the evidence bag and also reviewed the records kept to log the whereabouts of the cash as well as the results of a forensic examination of the bag for the fingerprints of those who had handled it.
Officers also established an audit trail to determine how and when the money was taken.
During the January raid, three men held up staff and customers at gunpoint before making off with the money.
A garda patrol blocked a car near the premises and recovered the cash.