Gardaí now say the young man whose body was found in a camper van in Co Westmeath was murdered.
This follows a post mortem which found the man died from blunt force to the body.
Originally the Gardaí said there were no obvious injuries to the body, following a preliminary examination.
However a full post-mortem revealed the man died from internal injuries cause by blunt force to the body -- and they've now upgraded their investigation to murder.
The victim was found in a camper van at Lough Lene in Collinstown about four this morning.
A man in his twenties has been arrested and is being questioned at Mullingar Garda Station.
Gardaí say they are not searching for anyone else at this time.