A 32-year-old man who went missing while snorkelling in South Australian waters on Thursday is believed to have been attacked by a shark, the state police said on Friday.

South Australian Police said that rescuers located a “damaged wetsuit” on Friday after finding snorkelling fins the previous night.

The items are all believed to belong to the missing man, according to the police.

The man, from regional Victoria, was snorkelling in the waters off Port Macdonnell in the state’s south-east when he went missing on Thursday afternoon.

A police helicopter spotted a shark in the area around that time.