Gardai suspect that the IRA may be behind the abduction of a 26-year-old man from Ballymun in north Dublin, who was taken from his home by men posing as gardai.
It is also suspected that the abduction is connected with the shooting of a local Sinn Fein councillor, Mr Larry O'Toole, at his grand-daughter's first Holy Communion in a Ballymun church two weekends ago.
The abducted man, Mr Kieron Byrne, is living with Ms Linda Birch, whose sister, Angela, is the partner of a man who is in custody in connection with the wounding of Mr O'Toole.
Some 40 gardai are involved in the search for Mr Byrne, who was taken from his flat in Ballymun at about 10.30 p.m. on Thursday.
Mr Byrne has a record of convictions for minor offences, but is not suspected of being involved in serious crime or in drug-dealing. It is believed there was a dispute in the area before the shooting of Mr O'Toole.
Gardai say the circumstances of the abduction suggest that IRA members have abducted Mr Byrne and have expressed concern for his safety.
The affair has given rise to concern that the incident might be a breach of the IRA ceasefire. Both the British and Irish governments have sought commitments from the IRA and its political wing, Sinn Fein, that it will desist from violence of all types.
The IRA has a record of carrying out attacks on people it has accused of drug-dealing and other activities. Sinn Fein was expelled from the talks process at Stormont in January after the IRA shot dead a Belfast drug-dealer, Brendan Campbell, and a loyalist, Robert Dougan.
The men who abducted Mr Byrne called to the flat he shared with his girlfriend and their child in Balcurris Road and identified themselves as detectives who were arresting him for questioning at the Bridewell Garda station. Mr Byrne was apparently convinced that the men were police officers.
Detectives said no violence was used in the abduction and the gang was convincing in claiming to be gardai. Mr Byrne went with them, but his girlfriend later telephoned the Bridewell to check how he was. Gardai told her that he was not listed there. All Garda stations in the Dublin area were then checked. When it became clear that Mr Byrne was not in any of them, a formal search was begun.
He is described as 5'9" tall and of stocky build with short brown hair. When he was abducted he had a week's growth of beard and was wearing a navy padded jacket, a white-striped navy tracksuit, a yellow T-shirt and black leather runners.
An incident room has been set up in Ballymun Garda station, and gardai there have joined detectives in Santry in the investigation.
Mr Larry O'Toole and his son, also Larry, were shot as they attended the first Holy Communion Mass of Mr O'Toole's eight-year-old grand-daughter. Mr O'Toole is a prominent anti-drugs campaigner in the Ballymun and Finglas areas. Both men are making satisfactory recoveries.