The family of Andrew Allen, who was murdered last year in Buncrana, have challenged his killers to say he was not a drug dealer or a career criminal.
Mr Allen, from Derry, was shot dead at his home near Buncrana on 9 February 2012.
Republican Action Against Drugs said it carried out the murder.
Speaking to the BBC Andrew's mother, Donna Smith urged people who know his killers to contact the police on either side of the border.
She said Andrew's death has had a huge impact on her family, including his two young children.
Ms Smith added that she has confidence in the Garda investigation into the murder and is satisfied with how the investigation is progressing.