Dissident republican Colin Duffy was arrested yesterday by murder squad detectives investigating the drive-by shooting of a prison officer in Northern Ireland.
He was detained with a second man in Lurgan, Co Armagh, just miles from where David Black, 52, was ambushed on the M1 motorway on his way to work at the top- security Maghaberry Jail, near Lisburn, Co Antrim.
A third man was arrested later last night in the Irish Republic.
Detectives leading the inquiry insisted they needed the public’s help to bring the killers to justice.
Superintendent Keith Agnew said: “Condemnation, however strident, is not enough. It needs to be translated into information if our investigation is to make maximum progress.”
Duffy, 44, who has been cleared of murder charges on three separate previous occasions – the latest last January after two soldiers were shot dead outside Massereene Army barracks in March 2009 – was arrested at his home in the Kilwilkie estate where republicans opposed to the peace process have huge support.
Politicians on all sides condemned the murder of the prison officer, who was planning to retire next year after more than 30 years of service.
Enda Kenny, the Irish Taoiseach who was in Armagh for talks with Northern Ireland First Minister Peter Robinson and Deputy First Minister Martin McGuinness, said the dissident republicans had been linked to criminality and drug dealing which had also led to deaths on the streets of Dublin.
Mr Black’s murder had overshadowed the meeting, he said.
He added: “We do not want to see a return to this, nobody on this island wants to see a return to this.”
Police yesterday confirmed the dark blue Toyota Camry car used by the gunman and then later burned out had Dublin-registered number plates.
Duffy and the second man, 31, are being held at Antrim, but detectives clearly believe it will be up to the public to give them the breakthrough they need.
Mr Black drove from his home in Cookstown, Co Tyrone, and minutes after pulling on to the motorway in his Audi A4, the car carrying the gunman pulled up alongside.
The killer opened fire after a passenger side window was lowered. Mr Black was hit, and his car then careered off the road and into ditch.
Police first thought there had been a motoring accident, but then realised the driver had been shot. Mr Black’s son even drove past 15 minutes later not knowing what had happened to his father.
Secretary of State Teresa Villiers said the terrorists would not succeed. She told the Commons: “The future of Northern Ireland will only ever be determined by democracy and by consent. That is a clear message coming from Northern Ireland in the wake of this tragedy, from political leaders, from church leaders and from across the wider community.”
Duffy is by far the most high-profile dissident republican in Northern Ireland and before his release in January, after being found not guilty of the murders of the two soldiers at Massereene, he was centrally involved in protests at Maghaberry Prison where some inmates had complained about conditions and having to undergo body searches.
He was previously cleared of involvement in two other murder cases.
Mr McGuinness claimed the dissidents had the support of only a tiny minority.
He added: “What you have to understand is that if you support these people you are effectively supporting people who are swimming in a sea of criminality and drugs, dressing it up on occasions in a flag of political convenience and you shouldn’t be under any illusions about that.”