An investigation is under way after a man in his 20s was found dead at a house in Swinford last night.
Gardaí attended the scene at around 10.50pm after receiving reports of a disturbance.
It is believed the victim died as a result of a serious assault.
A man in his 30s was arrested at the scene.
The body remains at the scene, which has been preserved for a forensic examination as Gardaí wait for the assistance of the State Pathologist.
Gardaí are appealing for anyone with information to come forward particularly anyone who was in the Swinford Town area between 8pm and 11:15pm yesterday evening.
They are urged to contact Claremorris Garda Station on 094 9372080, where an incidence room has been set up.