The bag a body was found in is distinctive, but the identity of the man remains a mystery.
Police on the NSW-Queensland border have renewed efforts to solve the mystery of an unidentified man whose body washed up on the banks of the Tweed River on November 24, 2012.
All they have to go on is that it was found in a distinctive, custom-made, plaid-patterned sleeping bag made of Indian cotton.
It's been four years and several fruitless public appeals since a shocked fisherman burst into the local pub about 7pm in the tiny town of Tumbulgum, telling staff he'd found a badly composed body in a bag in the river.
It's a case that has Tweed-Byron Local Area Command's Detective Inspector Brendon Cullen flummoxed.
Police can't work out who the man is, much less how he died.
Insp Cullen this week renewed calls for public information, with the sleeping bag the man was found in the focus.
"We just don't know who this guy is," he said.
"If we did, it would go a long way towards us finding out what actually happened to him.
"You don't often come across deceased people where nobody knows anything about who they are. Often we don't know how they died, but when it comes to knowing who they are we usually have a reasonable idea. Not in this case."
Police might resort to using facial reconstruction technology to shed some light, but for now the focus is the bag the body was in.
"The fabric is very distinctive, and it's not something you'd buy in a shop. It's been homemade," Insp Cullen said.
The bag is about 60cm x 165cm and is made of plaid Indian cotton. The material is blue and off white cheque.
"The bag isn't your normal sleeping bag. It's bag-like in its design, but there's no down in it, just cotton. It's stronger than a sheet, it's not a surfboard cover. It's just this mysterious bag which happened to have a body in it," Insp Cullen said.
"We're hoping whoever made it or knows where the fabric from might lead us to who he is."
The post mortem carried out immediately after the body was discovered left little to go on.
"The body was badly decomposed, and we couldn't really get a line of how and when he had died. The best guesstimate was around the two-week mark," Insp Cullen said.
The man was caucasian, aged between 50 and 70 years, was 163cm tall, and of thin build and had grey hair tied in a ponytail with a blue band. There were no teeth, indicating he may have worn dentures, and nixing the possibility of identifying him through dental records. The man was wearing only a pair of orange and blue underpants.
There was a small trace of alcohol in his system, which may mean he was drinking at a local pub or bought alcohol near where the body was found.
The post mortem couldn't determine the cause of death.
Early in the investigation, hippie communes and Hare Krishna camps near Byron Bay were the focus for police, because they "would attract a certain type of traveller - someone living a transient life and not necessarily letting people know their movements", Insp Cullen said.
"Those communes are somewhere where people can spend a couple of months at and then keep moving."
But missing persons checks and databases have failed to identify the body - although they did locate two other missing people.
"The bag is our best lead, but facial recognition technology is an option in the future, because we are just not getting any inroads with traditional means, so we may have to look outside the square," Insp Cullen said.