Stack murder team quiz IRA man in Spain
Detectives have travelled to Spain to interview an IRA man they believe ordered the murder of prison officer Brian Stack more than 30 years ago.
Mr Stack (47) was the only prison officer murdered by the IRA during the Troubles.
He was shot in the neck outside the National Stadium in Dublin after attending a boxing contest there. He died 18 months later.
The Provisionals consistently denied they were responsible for the 1983 shooting. Over the years they blamed it on a "rogue" unit, although this was dismissed by gardaí.
But after Sinn Féin president Gerry Adams and a former IRA "commander" met members of Mr Stack's family in 2013 the IRA issued a statement admitting they were responsible.
Fresh inquiries by a special team of detectives from the Garda National Bureau of Criminal Investigation (NBCI) have since made considerable progress towards establishing the identity of those believed to have been involved in the murder plot.
Two detectives flew to Spain and, with the co-operation of local police, interviewed the suspect at his home outside Alicante.
The man - who is from Belfast but had been living in south Dublin before moving to Spain several years ago - is regarded as being in charge of the IRA's so-called southern command at the time of Mr Stack's murder.
He is also suspected of being responsible for giving the go-ahead to members of an IRA Munster-based unit which shot dead Det Garda Jerry McCabe during a botched raid on a postal van in Adare, Co Limerick, in June 1996.
Gardaí believe Mr Stack was murdered by terrorists from a Dublin-based unit that included some Northern IRA members.
Mr Stack was a chief officer at Portlaoise - the top security prison that housed IRA inmates. He regularly reviewed internal arrangements there to prevent a terrorist jailbreak.
On the night of March 25, 1983, he had left the National Stadium and was walking across the South Circular Road towards his car when a gunman ran up behind him and shot him in the neck.
The gunman made his escape on a motorcycle, driven by an accomplice.
Mr Stack was left paralysed and brain-damaged after the shooting and died from his injuries 18 months later, in September 1984.
After a lengthy campaign by the Stack family, the Garda file on the case was reviewed by the force's "cold case" team and the NBCI team subsequently carried out fresh inquiries.
Detectives have now interviewed several people they think might be able to help them with their inquiries while others have yet to be interviewed.
Their discussions with the suspect in Spain will form a key part of a file that will be sent to the Director of Public Prosecutions (DPP) later in the year. The DPP will determine if criminal charges should be brought.
In its 2013 statement, the IRA said that when its "army council" determined that its "volunteers" had shot dead Mr Stack, the "volunteer responsible for the instruction" had been disciplined.
The Stack family later said that while the statement had brought them some closure, they were still left with unanswered questions.
The family have been critical of the garda investigations in the past and claim that there was major flaws with the original investigation.