A man arrested by Gardai investigating the murder of Andrew Allen has been released without charge.
The 24-year-old victim, who was from the Top of the Hill in the Waterside area of Derry, was one of a number of people intimidated out of the city by republican vigilantes.
He had moved to the Links View estate in Buncrana, Co Donegal, where he was blasted through a bedroom window after a group of men tried to break down the front door.
The attack, which took place on February 9, was later claimed by the Republican Action Against Drugs (RAAD) group.
A man in his 50s and from Northern Ireland, was arrested by Gardai in Donegal on Friday and released on Saturday morning after questioning.
A Garda spokesman said a file will be prepared for the Director of Public Prosecutions.