Rivera’s son was on the boat, but she was nowhere to be found. One life jacket was found on the boat and the boy was wearing another. Investigators found Rivera’s purse and her identification, but no other clues on the boat. Rivera has been presumed dead.
The lake remains closed to the public while the search continues.
“We don’t know if she’s going to be found five minutes from now or five days from now, so we’re still going to be continuing this effort,” said Capt. Eric Buschow, Ventura County Sheriff’s Office spokesman.
The Sheriff’s Office has teamed up with the Coast Guard and Tulare County searchers in the recovery effort. Investigators are using side-scanning sonar in water with visibility of only about a foot, Buschow said. A specially-trained dog is also being used in the search. The dog is trained to sniff just above the surface and alert handlers if they sense a body beneath the water.
The sonar equipment presented a couple images of interest during Thursday night’s search. Those areas have been searched, but nothing has been found.
Lake Piru is the result of a canyon that was dammed and flooded. It is about 2 miles long and about 130 feet deep at its deepest point.
“There is a flow to this lake,” Buschow said. “Even with that current, wherever she went down, they’re confident that that’s where she will be found.”
A plan to drop the level of the lake is planned for next month in order to do seismic retrofitting of the dam. That plan was in place well before Rivera’s disappearance, according to Buschow.
Detectives have spoken to Rivera’s son and as a result of that conversation do not believe Rivera made it to shore, he said.
CNN’s Faith Karimi, Dakin Andone and Stella Chan contributed to this report.