The U.S. Coast Guard on Monday suspended its search for a swimmer who was reportedly attacked by a shark and pulled under over the weekend in the waters off Point Reyes National Seashore in Marin County.

A search and rescue had been underway Sunday involving the Marin Fire Department, the National Park Service, the Marin County Sheriff's Office and the Coast Guard.

The swimmer, whose name has not been released, was reported missing near a remote area called Wildcat Beach about 10:30 a.m. Sunday.

"The U.S. Coast Guard suspended its search in the frigid waters this morning, but a ground search is being conducted by first responders from the NPS, the Marin County Sheriff's Office and the Marin County Fire Department, and the Stinson Beach Fire Department," according to an advisory from the National Park Service.

The search was initially conducted by land, water and air, officials said.

A witness at the scene of the apparent attack told The Standard the victim had previously been celebrating a wedding and, afterward, had gone backpacking with a group of wedding guests when the incident occurred.

Samantha Edell told The Standard about alerting emergency services to the attack when camping with her son on Sunday.

"My son came up to me, and he said he heard some screaming," Edell, who lives in Castro Valley, said Monday. "We came out, and a group was gathered around that area where the water is, and they were looking for someone who could call emergency services because there's no cell service there."

After Edell brought members of the group up to her campsite, they asked her if she could call emergency services. She did so using her Zoleo satellite communicator—a device that extends cell phone coverage and makes emergency calls.

"They told me that their friend was out swimming, and he was attacked by a shark," Edell said. "I said, 'How bad is it?' They said he never came out of the water."

After hitting the SOS button on her device, she followed a group down to the beach, where another man said he was already in contact with emergency services.

"There was another man on the beach who had an iPhone that had satellite facilities. He was already in contact with emergency services, so I ended my SOS call," Edell said. "He said that they were on their way already and to go up to the top part of the campground and to wave them down when they got there."

Edell said a woman in the group told her they had just attended a wedding and had gone backpacking together after the event.

"I told her to keep an eye out for the rescue people, that they were on their way," Edell said. "It was a large party. People came in from all over, as far as Europe."

She said it was the first time she had ever used her satellite device.

This is a developing story.