The source continued: "The tourist and his wife were spending a week on the island and he had gone out swimming in the Hermitage Lagoon, off Saint-Gilles, alone on Saturday.
When he failed to return, his wife sounded the alarm and a full search was launched, involving boats, divers, dogs, and a helicopter.
"Sadly, the man could not be found."
There are frequent shark attacks around Reunion.
The suspected attack victim has not been named but is said to be a British national from Scotland.
Tiger sharks are second only to Great White sharks in terms of their attacks on humans, but it may be that the man drowned and his corpse attracted the fish. Swimming and other water activities are heavily restricted on Reunion due to the high risk of shark attacks.
DNA tests are due to be carried out, but scientists from the CSR Shark Safety Centre on Reunion have been told that the wedding ring "conformed to one identified by the man's wife," said the source.
The dead shark was more than 3 metres long and was one of five considered a threat to those in the sea.
