Police in the western port city of Patra on Thursday were looking for information into the identity of a man found dead outside a hospital in the neighboring town of Rio.
The man is believed to be aged in his mid-50s and was not carrying any identification documents.
An autopsy did not reveal any signs of trauma, leading investigators to believe that he may have been homeless and died of exposure to the cold.
He was found by medical staff hunched up in a remote corner outside the hospital’s morgue.
There was some speculation as to whether the man had been a patient at the Rio hospital and had left before doctors were able to treat him, as some reports had suggested on Wednesday, or whether he perished on his way to asking for help.