county sheriff's department used boats and a dive team to search tomales bay. that couple is from palo alto, and was last seen on friday. good evening, everyone, i'm heather holmesjulie. >> i'm frank somerville. for the fourth straight day, the search wrapped up with nothing to show for it, but tomorrow, they'll be back at it. with us tonight from inverness, rob. >> reporter: the search continued with no signs of the missing couple. searchers say each time they go their chance for survival decreases. searchers found nothing. >> our dive rescue team brought a remotely operated vessel, which includes camera capabilities for searching underwater, as well as sonar. >> reporter: the search centered around the waters near shell beach one, and shell beach two, the nearest beaches to where the couple was staying in inverness. >> we attempted to look at them using underwater resources, as well as our resources on top of the water. >> reporter: carol kiparsky, and 72-year-old ian irwin was last seen friday afternoon, near the cottage they rented. authorities believe they may have gone on a hike, and gotten lost. their phones and other belongings were still at the cottage.