Sydney John Doe was a man discovered in Sydney, Australia on 11 April, 2018.
The man was found hanging in a street in Campsie, a suburb of Sydney. The only clue to his identity was an Opal card, which is an electronic card used for transportation. Through this, it was discovered that he always took a bus to and from a bus stop called "Dan's Corner" and the card was topped up with cash at a location that did not have security cameras.
The post-mortem revealed that he was probably suffering from a type of blood cancer called multiple myeloma, known to cause excruciating pain.