Gardai believe people are with-holding information which could help them find the killers of Andrew Allen.
The 24 year old was gunned down in Buncrana in February, 2012.
Now on the fifth anniversary of his death, Gardai have issued an appeal to anybody who may have information on the cold-blooded killing to get in touch.
Mr Allen’s partner miraculously escaped injury when gunmen burst into their home at Links View Park and fired a number of shots.
Gardaí have said that the 24-year-old had moved to Donegal after he became the target of the vigilante group Republican Action Against Drugs in his native Derry. The dissident group claimed responsibility for the murder.
Now, five years after his murder, gardaí have again made an appeal for anyone with information to come forward.
A spokesman said “To date a number of people have been arrested and questioned in connection with the investigation.
“An Garda Síochana are grateful for all the witnesses that have come forward and made statements but gardaí believe that there are still people in our community who have information which may assist the investigation.”
Throughout the investigation, gardaí have worked closely with the PSNI.
Anyone with information is urged to contact the incident room at Buncrana Garda Station on 074 93 20540 or use the Garda Confidential Telephone Line 1800 666 111.