The 24-year-old was killed in front of his partner in his home
Gardaí are issuing a renewed appeal for information about the murder of Andrew Allen.
The 24-year-old was killed in his home at the Links View Park, Buncrana in Co Donegal in front of his partner on February 9th 2012.
He received a number of gunshot wounds and was pronounced dead at the scene.
A car - a silver Vauxhall Cavalier, believed to be involved in the murder - was on fire at Churchbrea, three miles outside Buncrana, shortly after the shooting.
Gardaí believe a number of people were involved in planning this murder, the destruction of evidence and subsequently sheltering those involved.
To date a number of people have been arrested and questioned in connection with the investigation, including one in April 2017.
An Garda Síochána say they are grateful for all the witnesses that have come forward and made statements - but believe that there are still people in both Buncrana and Derry city who have information that may assist with the investigation.
They are appealing for anyone with information, or who can assist with this investigation, to contact the incident room at Buncrana garda station on 074-93-20540, the Garda Confidential Telephone Line at 1800-666-111 or any garda station.
They particularly want to speak to anyone who may have seen suspicious activity around the scene of the shooting prior to the incident, or where the burning car was located in Fahan before or after the shooting.