Police are appealing for help identifying a "vulnerable" man who was found in a bus station car park four months ago.
Officers say the man, who gave his name as Roger Curry and speaks with a North American accent, says he has "no memory" of who he is.
He was found in Hereford on November 7 and is in council care while the police continue their inquiries.
West Mercia Police said it wants to trace a man, described as being in his 40s, who was seen to be walking with Mr Curry towards the Hereford County Hospital on the day he was discovered.
The force said Mr Curry is tall, slim and was found wearing a black hooded top and black jogging trousers.
Police are keen to find out if he has been reported missing nationally or internationally.
Detective Sergeant Sarah Bennett, of West Mercia Police, said "We are appealing locally, nationally and internationally to anyone who can help us trace the man who was seen with Roger.
"He may have vital information that can help us piece together where Roger had been prior to him being found. Any information, little as it may be, could be the key to unlocking this mystery.
"This is an unusual situation and we are desperately hoping that we can reunite Roger with his family, wherever they may be."