UPDATE, March 7: The injured man has been named as Jonathan Czunys of Penryn. He has a five-year-old son.
Police have renewed their appeal for witnesses to come forward - they are particularly interested in any information on a black, Toyota-type vehicle seen near the scene.
Mr Czuyns is said to be making "slow progress" and is still in intensive care.
A Penryn man with a fractured skull and injuries to his face and brain was found outside a Truro hotel on Sunday morning.
The 26-year-old man was spotted by a member of staff at Alverton Manor Hotel, on Tregolls Road, while they were on their way to work at 7am.
He was last seen on CCTV near the Trafalgar roundabout at 12.30am, walking towards the hotel where he had a room booked.
What happened in the intervening six and half hours remains a mystery.
Inspector Mark Richards said the police were “keeping an open mind” but wanted to know how the victim got his injuries.
At the time of going to press the man was said to be in a serious condition at Derriford Hospital where he is being treated for head, shoulder and rib injuries.
Police officers are working on the theory that he may have been hit by a car - possibly a Toyota.
Anyone with any information on what happened to the victim, or who knows of any vehicles that sustained fresh damage over the weekend, can contact the police on 101 ref GT/13/373.