Gardaí in Carrick-on-Shannon are not looking for anyone else in connection with an incident in the town early Monday morning.
A young man was found in a serious condition with head injuries at Bridge Street at approximately 4am.
Initially it was thought the man was a victim of an assault and the scene was sealed off for a technical examination.
Gardaí now do not believe an assault took place.
The man was removed to hospital with serious head injuries.