MELBOURNE, Australia — Emergency services responded to a suspected fatal shark attack off a Western Australian city beach Friday.

A police boat and helicopter were sent to Sorrento Beach in Perth’s northern suburbs after a possible shark-related incident, a police statement said.

Western Australia state wildlife officers were also investigating the reported incident, a government statement said.

Witnesses reported seeing blood in the water.

“My friend said, ‘Jac, I think there’s been a shark attack,’ and I looked out to the ocean and I could see a pool of blood,” beach walker Jacqui Rapaic told Australian Broadcasting Corp.

Local Ryan Rowe reached the beach soon afterward and said he was was told by an onlooker “someone had been bitten by a shark.”

“I couldn’t believe there was that much blood (that had) come out of a human body,” Rowe told The West Australian newspaper.

Authorities closed the beach to swimmers.

A surfer sustained a serious leg wound in a shark attack Monday near Geraldton, about 400 kilometers (250 miles) north of Perth.

There have been four confirmed fatal shark attacks in Australia this year.

Three spearfishing divers were killed by sharks off the Australian coast in four weeks over May and June. In January, a 12-year-old boy died in a hospital days after he was mauled by a bull shark in Sydney Harbor.

Australia has averaged between two and three fatal shark attacks a year since 2000, according to the Australian Shark Incident Database, a partnership of the Taronga Conservation Society Australia, Flinders University and the New South Wales state government.