The conviction of a south Armagh man for the capital murder of Detective Garda Adrian Donohoe paves the way for police in the Republic to put five more men involved in his killing - some from Northern Ireland - behind bars.
A jury at Dublin's Central Criminal Court found Aaron Brady (29) guilty of shooting dead Mr Donohoe during the robbery of Lordship Credit Union in Bellurgan on January 25, 2013.
The Crossmaglen man now faces a minimum 40-year prison sentence. The charge of capital murder includes an aggravating factor, such as murdering a police officer while on duty.
Garda Donohoe's widow Caroline, who was a serving garda herself at the time of the murder, spoke briefly outside court after the verdict was returned. She thanked those involved in bringing Brady to justice on behalf of herself and her two children.
"I would like to most sincerely thank the jury for sticking with this trial for so long and for my Garda colleagues and the prosecution team on behalf of Amy, Niall and myself, thank you very much," she said.
Detectives are actively pursuing further prosecutions in relation to the robbery and shocking murder.
Mr Donohoe (41) had been on duty in Co Louth when he was killed with a shotgun blast.
Five people have been formally classified as suspects in the murder investigation and these men are now the prime targets for gardai.
Speaking after Brady (29) was convicted of capital murder, Garda Deputy Commissioner John Twomey warned those involved in the credit union robbery that investigators "will be knocking on your door and make sure that you pay for the horrendous act".
Over the last seven years the massive investigation into Garda Donohoe's killing has identified 204 persons of interest, and that list has been whittled down to over 20 people who gardai believe were either involved or are harbouring the robbery gang.
Speaking after the trial yesterday, Chief Supt Christy Mangan said Brady's conviction was just the first phase and that they will continue to track down others involved as part of the international inquiry.
"They murdered Adrian, they left the scene and went into Northern Ireland and then they thought that borders would save them, but borders didn't save them. We will be continuing with our relentless pursuit of all the other people who were involved in this murder-robbery," he said.
"There are people who provided logistical support after the robbery and the murder of Adrian, so we're very interested in dealing with them as well."
The list of formal suspects includes a father and his two sons who lived close to the scene at the time of the robbery.
A notorious border criminal, suspected of orchestrating a number of high-profile ATM raids in the past two years, is also listed as a suspect. He is currently in jail facing charges over separate matters.
The fifth person, a young man at the time of the murder who comes from a major smuggling family in Armagh, is the youngest of the suspects and is being investigated for taking part in the robbery.
Suspect A was best friends with Brady at the time of the fatal shooting and is under investigation for being centrally involved in the robbery.
The man, was frequently named throughout the trial by the prosecution as Brady's accomplice but cannot be identified for legal reasons.
At the time of the murder he lived a short distance away from Lordship Credit Union and was with Brady on a daily basis in the week leading up to the robbery.
His distinctive car was linked to several key sightings during the murder, including a "scoping exercise" that afternoon and the robbery of the getaway car.
Since the murder the suspect has become a father and has married.
He currently lives between Boston and Northern Ireland, although his wife, who is facing serious charges in an unconnected case, remains in the Republic.
A prolific border criminal, Suspect B has been centrally linked to the stealing of the getaway car and is also suspected of helping to plan the raid.
He was on bail at the time of the murder and signed on at Crossmaglen police station just over two hours before the crime.
Even before the raid, he was well-known to gardai for involvement in serious crime and was arrested by Det Gda Donohoe for the previous armed robbery at Lordship Credit Union in August 2011, as well as a separate armed raid at Dundalk racecourse that same year.
During his arrest he made a sinister threat to Det Gda Donohoe, stating he knew where the detective's family home was located.
Properties linked to him and his sister were raided by police.
It can also be revealed that Suspect B is under investigation for orchestrating a number of high-profile ATM raids on both sides of the border which have netted his gang hundreds of thousands of euro and pounds.
In one incident he narrowly avoided arrest after gardai foiled an ATM raid.
However, the criminal's luck ran out weeks later when he was detained for a separate offence in Dundalk and later charged.
He is currently being held on remand, with senior officers objecting to attempts for him to secure bail.
A man from a major fuel smuggling family, Suspect C, was one of the youngest men at the time of the robbery.
He was named in Brady's notice of alibi as directing him to move fuel waste cubes at a diesel yard that night, but during the trial it emerged he is a suspect.
He fled the country less then two months after the killing, and has also been targeted in firearms searches by the PSNI.
Two other men who are suspected of assisting the gang are the Boston suspect and his father.
Both men are relatives of Suspect A and are being investigated for involvement in the car robbery and scouting on the night of the murder respectively.
Two other men are formally classified as persons of interest, although both are suspected of actively taking part in the robbery that night.