(CNN) -- Two Irish Republican Army dissidents were found guilty Friday of murdering a police officer in a killing that shocked Northern Ireland three years ago.
Catholic constable Stephen Carroll, 48, was shot dead when paramilitaries used an emergency call to lure police into an ambush in Craigavon, County Armagh, in March 2009.
The Continuity IRA admitted it set up the attack, which took place just 48 hours after two British soldiers were killed by another splinter group, the Real IRA, in an ambush outside an army base in Antrim, Northern Ireland.
The killings led to ex-IRA commander Martin McGuinness describing dissidents as "traitors to Ireland" -- a comment that led to his life being threatened by groups that contain old comrades. McGuinness is now deputy first minister in Northern Ireland's power-sharing government and, along with the mainstream IRA, has renounced violence.
One of those found guilty Friday of the police officer's murder -- Brendan McConville, 40 -- was formerly an elected public representative of the Sinn Fein party led by McGuinness and Gerry Adams.
The other man convicted -- John Paul Wootton, 20 -- was just 17 at the time of Carroll's killing. Both men are from the district where the gun attack took place.
The accused chose not to take the stand to defend themselves, but through their lawyers maintained their innocence throughout the nine-week trial at Belfast Crown Court.
However, Friday, the judge, Lord Justice Paul Girvan, said forensic and witness evidence proved the men were "intimately involved" in the killing.
The judge added that both defendants were "active and committed supporters of a republican campaign of violence."
Girvan branded the killing "callous and cowardly" and said Carroll was shot dead simply because he was a police officer.
The judge said the two murderers deserved life in prison. The minimum amount of time they must serve before being considered for release from prison will be set at a future hearing.
Constable Carroll's widow, Kate, embraced her son when the guilty verdicts were delivered.
Wootton's mother had in February pleaded guilty to obstructing the investigation into the killing.
Sharon Wootton, 39, admitted moving computer equipment from her home to another address after police raids on the house.
Carroll was the first member of the Police Service of Northern Ireland to be murdered on duty. The force was called the Royal Ulster Constabulary before a reorganization in 2001.
Over 300 members of the constabulary were killed and almost 9,000 were injured during the Northern Ireland conflict between pro-British and pro-Irish forces.
IRA splinter groups have remained active since the signing of the Good Friday peace agreement in 1998.