His body was found at a property in Millmount Court in Banbridge on Monday afternoon.
A post mortem examination will take place to determine the cause of death.
Detectives say that at this stage his is being treated as suspicious at this time.
During follow up inquiries, a 28-year-old man has been arrested and remains in custody for questioning.
MIT detectives are appealing for anyone with any information that can assist with the investigation to contact them in the incident room at Banbridge Police Station.
Officers want to speak with anyone who was in the area of Millmount Court between Saturday, July 7 and Monday, July 9, and who noticed anything suspicious to contact them on the 101 number.