On Wednesday, actress Naya Rivera went missing after a boat she had rented was found in Lake Piru, in Ventura County, California, with her 4-year-old son, Josey Hollis Dorsey, onboard.
NBC station KNBC reported that the search for the 33-year-old star of "Glee" resumed Thursday morning, but the sheriff's department said the effort is now considered a recovery operation.
Ventura County Sheriff's Department officials said, "This is considered to be a horrible accident."
"I can't make any sense of what happened," said Ventura County Deputy Chris Dyer. "We just know that we found a 4-year-old on a boat, and he said that his mother never got back in."
"So, right now, we're viewing this as a tragic accident."
The 33-year-old from Woodland Hills had been boating with her son, whom she shares with ex-husband Ryan Dorsey. The actress rented a boat at about 1 p.m, officials said, and three hours later, authorities found her son napping alone on the vessel. The child had a life vest on but officials believe Rivera did not, as an adult life vest was found on board the boat.
"Multiple teams of professional search & rescue personnel are actively searching Lake Piru for clues to the location of Naya Rivera," a tweet from the Ventura County Sheriff's Department said on Thursday. "With over 80 people involved in the search right now, we are using helicopters, boats, ATV vehicles, and ground personnel to try and locate her."
Another tweet said, "We have mutual aid for specialized dive teams en route from Los Angeles County, San Luis Obispo County, and Tulare County. We will keep you posted with any updates as we learn them. Our hearts and prayers go out the all of the family and friends of the Rivera family. #sheriffvc."
Ventura County Sheriff's Department told NBC News Thursday afternoon that the site of the search, a man-made reservoir up to 130 feet in spots and loaded with debris, poses challenges and safety issues.
Rivera is best known for playing Santana Lopez on "Glee," a high school glee club musical and comedy that ran on Fox from 2009 to 2015.