The Palo Alto couple were last heard from on Friday, but they were reported missing when they didn't check out of their Airbnb rental in Inverness on Saturday.
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Four days into this search, the investigation shifted from land to water.
"We had a side-scan sonar on a National Park Service boat, we used both boats, we had a dog out there trying to detect scent, and we had nothing turn up," says Sgt. Brenton Schneider with the Marin County Sheriff's Office. "The water conditions were very favorable for both (boats), and we had no indication of Carol or Ian in the water, so the scuba divers did not go into the water."
Rescue teams have already covered a two-mile area of Point Reyes National Seashore and the area around the Airbnb rental where the couple was staying.
UPDATE: Rescue teams finish searching water near Shell #Beach and Tomales Bay for missing #PaloAlto couple. Sheriff’s Office says teams found no new evidence. Next search planned for Thursday and Saturday. @PointReyesNPS#BayArea #PointReyes #Inverness https://t.co/boWXNneonK pic.twitter.com/cIwiTe0Wdn— Anser Hassan (@AnserHassan) February 19, 2020
They have mapped out areas they searched, but it now may require going back out for another look.
"I know the search managers are taking a look at all the tracks from the GPS devices that we have had on searchers. If there are possible way we missed any spots, we want to check spots again," says Schneider. "The (family is) sad, they are worried about Carol and Ian, and they want them to come home safely. So, that's why we are still out there searching."
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Detectives have been looking into the financial records of the couple, which hasn't produced any new leads ether.
Erica MacDonald used to live in Inverness. She came out with her kids to Shell Beach, one of the areas crews searched. She hopes the family will be reunited.
"It is a bit shocking, but who knows what happened. Hopefully, they are ok and maybe just not able to be reached right now, who knows," says MacDonald.
"Of course, it's a concern. Because nothing like this has ever happened around here," says Jose Ramo. He has worked construction in the area since the 1980s.
He says this investigation has been the talk of the town. He praises the hard work of the search crews, many who are volunteers.
"Lots of volunteers around, some are locals. They are trying their best to find (them)," he says.