A man arrested in connection with the murder of Andrew Allen in Co Donegal in February has been released without charge, gardaí said.
Mr Allen (24) was killed when a gang fired shots through his windows.
A man in his 50s, from Northern Ireland, was detained at Buncrana Garda station in Co Donegal on Friday under section 50 of the Criminal Justice Act.
The group Republican Action Against Drugs claimed it killed Mr Allen, a father of two, because he was a drug dealer – a claim denied by his family.
The man is the first person to be arrested in connection with the killing.
Mr Allen had been living Links Park in Buncrana after he was ordered to leave Derry some months before his murder.
Gunmen arrived at his rented home on February 9th and when they could not get in the front door, they shot into his bedroom. Mr Allen died at the scene.
A Garda spokesman said a file would be prepared for the Director of Public Prosecutions.