A man in his 20s who had been detained at Claremorris Garda Station in relation to the death of Joseph Deacy in Swinford, Co Mayo, last year was released without charge last night.
A file will be prepared for the Director of Public Prosecutions.
Mr Deacy was found with head injuries outside a house at Gortnasillagh on 12 August.
The 21-year-old, from St Albans in England, was initially taken to Mayo University Hospital.
He was later transferred to Beaumont Hospital, where he was pronounced dead the following day.
