A California triathlete whose body washed ashore a week after she vanished during a group ocean swim off the Monterey coast was killed in a gruesome shark attack, according to a newly released report.

Erica Fox, 55, disappeared in December 2025 while swimming with 14 others in the frigid waters off Monterey.

A week later, her body was discovered about 25 miles away near Davenport Beach in Santa Cruz County, still partially dressed in her black wetsuit, the report said.

The Santa Cruz County Sheriff-Coroner’s office revealed this week that Fox was killed by “sharp and blunt force injuries and submersion in water due to a shark attack,” the Monterey Herald reported. 

Authorities said that Fox’s swimsuit and wetsuit were torn where her injuries occurred, with a “semi-circle of tooth wounds” extending from her abdomen to her knees.

The report said that the single bite from her torso to her legs from the shark fractured her pelvis and “severed a major artery.”

Chris Lowe, a professor of marine biology with the Shark Lab at California State University Long Beach, said he suspects the shark thought Fox was a seal or sea lion.

“The only explanation we can come up with in cases like this is that the shark made a mistake,” Lowe said. “It mistook a person for a seal or a sea lion.”

“This was a big shark. I think she was probably knocked unconscious immediately. It was a horrible trauma.”

Fox was participating in a weekly swim with a club she co-founded with her husband Jean-Francis Vanreusel — called the Kelp Krawlers in Pacific Grove — when the group feared a “large splash” was an attacking shark, KSBW reported.

While the other swimmers all made it back to shore, Fox remained missing.

The autopsy appears to confirm witness reports at the time of seeing a shark with a human body in its jaws before it submerged, per the Coast Guard.

A post Fox once shared on social media showed a picture of a diver swimming alongside a great white shark.

“This is the most DANGEROUS ANIMAL in the world, and by his side, a SHARK swims peacefully,” the post was captioned.

The Facebook page for the Kelp Crawlers includes photos of Fox and the swimmers in the group with a message at the top that said it’s closed. 

There’s also comments talking about Fox’s tragedy, appearing to back up Lowe’s theory that the shark didn’t know she was a human.

“So Sad About Erica Fox. Has anyone ever investigated developing a wet suit that looks less like, black outline of prey, and maybe like some other thing?” one person wrote.

“Maybe a Orcas pattern or have the scent of Orcas come for the wet suit.”

“Scientists at Macquarie University recently found that horizontal stripes of steady LED lights placed on the underside of objects can effectively deter great white shark attacks,” another added, noting a report in The LighthouseTechnology Networks.

Fox’s death is now the third shark attack at Lover’s Point since June 2022, when fellow Kelp Krawler member, Steve Bruemmer, then 62, was bitten on the leg and only survived after he was rescued by nearby paddleboarders, according to Monterey County Now.