MELBOURNE, Australia (AP) — A man was killed by a shark as he swam off a Western Australian city beach Friday while beachgoers watched in horror.

Boats and helicopters searched the ocean off Sorrento Beach in Perth's northern suburbs after the late-morning attack, a police statement said. Police would not say whether potential remains had been found.

But police were confident the “swimmer died as a result of the attack,” the statement said.

A witness to the attack, Darrel Haythornthwaite, told Nine Network television that the victim had been swimming with a now traumatized friend.

“I was just shocked. I mean, I feel for his mate. He's apologized and said 'I didn't save my mate,'” Haythornthwaite told Nine. “I said, 'You couldn't have done anything.'”

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.

Ryan Rowe, a resident, told The West Australian newspaper that he reached the beach soon afterward and 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 said.

Authorities closed the beach to swimmers. Witnesses described the swimmer as a man in his 60s but police did not identify him further.

In a separate shark attack, a surfer sustained a serious leg injury Monday near Geraldton, about 400 kilometers (250 miles) north of Perth.

There have been five 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 including Taronga Conservation Society Australia, Flinders University and the New South Wales state government.