The interim Garda Commissioner said she is determined that the people who murdered Adrian Donohoe will be pursued and apprehended.
"We are very, very determined that the people who murdered [him] will be pursued and will be apprehended," said Noirin O'Sullivan, interim Commissioner.
"We're having very, very good cooperation with the PSNI and our colleagues in the US authorities and I'm very confident that the people that murdered Garda Donohoe will be brought to justice."
The Detective Garda was shot dead during a botched robbery at the Lordship Credit Union outside Dundalk in Co Louth in January 2013.
Gardaí previously stated they are satisfied that they have identified the gang members involved, but no arrests have yet been made.