Basically strange events have been happening in warmer regions of the of the world. Whales with bite marks half way through them washing up on beaches. And a fishing trolley was sunk near South Africa, they thought initially that a whale had breeched and capsized it but determined that it was actually rammed from below, the way a shark attacks.
Add to that a few pictures of dorsal fins six feet high, both recent and historical and local legends of sharks anywhere from over 30 to 75 feet long. Some marine biologist think it is megladon, a shark thought to have been extinct 2000000 years that could grow up to 100 feet long.
Some think megladon is a lazerus taxon, an animal thought to have gone extinct then reappeared at a later date. A tooth was found recently from a megladon that was radio carbon dated to be about 10,000 years old.
In recent years changes of the ocean floor and shore line caused my massive quakes and super storms along with climate change have forced many animals to seek out new habitats and change migration patterns. It is believed these factors may have forced megladon in to new hunting grounds and led to encounters with people. How awesome is that?!