A Co Limerick man, who is understood to have been living recently under an alias in Dublin, may appear in court today on an IRA membership charge. He was arrested in the Rialto area of Dublin on Tuesday.
At the same time another man and a woman were also arrested in the city by gardai investigating the murder of Garda Jerry McCabe, who was shot in Adare in June last year.
Garda McCabe was shot dead and his fellow officer Garda Ben O'Sullivan seriously injured when an IRA gunman opened fire on their car.
The officers were providing an escort for a post office cash delivery at the time.
Several people have been questioned about the murder, which was carried out by an IRA gang from the south-west region.
The three people arrested in Dublin were detained under the Offences Against the State Act, which allows their detention without charge for two days. They were taken for questioning to Henry Street Garda station in Limerick.