The sunken bell of the doomed Costa Concordia cruise liner has gone missing, prompting a bout of head-scratching from Italian authorities over how exactly it was removed, the ANSA news agency reported Thursday.

The metal bell was attached to the sunken bow of the ship, which came to grief on rocks off the Mediterranean island of Giglio on January 13, claiming 32 lives.

Iconic photos of the rescue and recovery effort showed divers swimming near the sunken bell, which was 26 feet below the surface.

But several days ago, the bell mysteriously disappeared, leaving authorities at a loss for answers, ANSA reported.

If it was a case of theft, it would be no mean feat. The partially-submerged ship is off-limits to everyone except rescuers, investigators and technicians, and it is patrolled by the Coast Guard. Furthermore, the bell weighs more than 22 pounds, meaning it would likely take more than one diver to remove it.

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The bell was supposed to be given to residents of Giglio, an island off the Tuscan coast, once the recovery and cleanup work was complete, the report said.

The Costa Concordia ran aground with over 4,000 people on board. The captain, Francesco Schettino, was later arrested and faces charges of abandoning ship and manslaughter.

For more information on the Costa Concordia shipwreck see NewsCore