Researchers had tagged the healthy nine-foot great white to track its movements as part of a study but were shocked when the "black box" washed up on a beach in Australia four months later.

Filmmaker Dave Riggs said in 2014: “When I was first told about the data that came back from the tag that was on the shark, I was absolutely blown away.

According to the researchers who investigated the puzzling case, it was a “colossal cannibal great white shark".

It was only after further study of the migration patterns – of the great whites that came into the area where the 9-footer was killed – that they finally could guess the identity of the mysterious killer.

The body temperature of these migrating great whites was the same, and the size of the cannibal great white shark – which they estimated to be 16 foot long and weigh over two tonnes – could easily pull off the same speed and trajectory captured in the tracking device.

READ MORE: Shark bombshell: How landmark study rewrites link between Megalodon and great whites.

This is threatening the natural food chain of the area, which could completely collapse if great whites have no source of prey