Updated

Authorities are investigating the mysterious death of a San Diego surfer whose body was found covered with shark bites.

San Diego Lifeguard Lt. John Everhart says someone walking on the beach discovered the body before dawn Thursday.

Authorities believe the body is that of a 42-year-old man who was reported missing by his fiancee Wednesday night after he did not return from surfing. Neither the man's name nor the name of his fiancee have been released, Fox 5 reports.

Everhart tells Fox 5 that the man's surfboard was found separately with his wetsuit tied around it, a detail Everhart found odd.

“I’ve been doing this 30 years almost and I’ve never seen someone do that,” he said.  “It’s just a very strange decision to make when you’re out on the water.”

Everhart says the body had wounds consistent with a shark attack, but there were no obvious signs of a struggle. The medical examiner concluded the attack occurred after the surfer had died.

Fellow surfer Neil Ratnavara tells Fox 5 he believes saw the man before he vanished.

“I just saw him paddle off shore out there, going north just by himself,” Ratnavara said. “There were still a few people in the water.  Not too many waves, but there was nothing odd about that.”

The man's death is under investigation.

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The Associated Press contributed to this report.