A man has been found with severe head injuries in King's Lynn, but Norfolk Police say they do not know his identity or how he came to be so badly hurt.
The victim was found on the Walks in the town near Blackfriars Road on Wednesday evening.
He was taken to the Queen Elizabeth Hospital in the town and is said to be in a critical but stable condition.
Because of the extent of the man's injuries officers have been unable to talk to him.
He is described as being in his mid 20s, about 5ft 10ins tall with short brown hair and bushy eyebrows.
He was wearing a grey hooded top, dark jeans and white Nike trainers.