And a source has revealed that the criminal tracked down by gardai in Sydney provided officers with at least some explanations when he was questioned.
This is in complete contrast to the two men who had fled to New York and refused to answer any questions when they were quizzed about the murder of the garda at the Lordship credit union in Co Louth.
Sources said that "major movement" is expected in the case in the coming months, with the three men who fled abroad due to be returned home and ongoing surveillance continuing on the other two men who are based in south Armagh.
It is understood that gardai have "an absolute wealth" of CCTV and mobile phone evidence in the case, and are also in a position to charge the gang with a series of other crimes including armed robbery as well as possession of firearms and attempted robbery.
Last weekend, the Herald revealed that detectives have made what they called significant progress in linking the stolen car that was used in the murder to the gang.
A source said: "It is all coming together well at the moment – there is a lot of confidence that this gang will be charged and put out of circulation.
"This has been one of the biggest investigations in the history of the State."
The suspects, including the criminal who is believed to have fired the shotgun at the detective, cannot be extradited unless the Director of Public Prosecutions rules that they should face criminal charges.
Gda Donohoe was blasted in the head with a shotgun when he confronted a gang on rural roads near his home on the Cooley peninsula.
The five-man gang, which includes two brothers, are all from south Armagh.
It is understood that the PSNI has quizzed a number of the gang members believed to have been involved in the murder, including a woman who provided an alibi for her boyfriend who is suspected of having been at the scene.
Meanwhile, an anniversary mass for Gda Donohoe will take place at the Redemptorist Church, Dundalk, tomorrow at 7.30pm.
And a candlelight walk will take place from Lordship credit union in Bellurgan, Co Louth, to the St Patrick's GFC grounds on Saturday night.
The event gets under way at 9.15pm from the credit union, where there will be a short period of reflection followed by the walk to the GAA grounds – a club of which Gda Donohoe was a proud member.