The Garda Commissioner is warning the five members of the gang involved in the murder of Adrian Donohoe to "keep looking over your shoulder".
The Detective Garda (41) was shot dead during a robbery at the Lordship Credit Union near Dundalk in Louth a year ago tomorrow night.
Martin Callinan says gardai know the identities of the people who carried out the attack, but he says people are shielding the suspects.
A candle & flowers at Lordship Credit Union where Garda Donohoe was murdered
Over 2,000 statements have so far been taken and around 400,000 hours of CCTV footage examined as part of the inquiry.
The Garda Commissioner is appealing to people on both sides of the border with information to come forward - insisting that they will be protected.
Meanwhile a memorial service will take place in Dundalk in Co. Louth to mark the first anniversary of the murder.
The Donohue family will be joined by the Justice Minister and Garda Commissioner for the mass in St. Joseph's Redemptorist Church this evening.
The local GAA pitch at St. Patrick's Club in Lordship named in Adrian Donohoe's honour
The Chairman of St Partick's GAA Club in Lordship is Alan Duffy. He told Newstalk Breakfast earlier the community was still struggling to accept what happened.
