LOS ANGELES - A body was found Monday at a Southern California lake during the search for "Glee" star Naya Rivera, authorities said.

The body was discovered five days after the 33-year-old Rivera disappeared on Lake Piru, where her son was found July 8 alone a few hours later on a boat the two had rented, the Ventura County Sheriff's Office said.

Authorities would not immediately say if the person found was Rivera, but said the day after she disappeared that they believed she drowned in the lake northwest of Los Angeles. A 2 p.m. press conference was scheduled.

Search crews found the body floating in the northeast area of the lake and the county medical examiner was notified, authorities said.

The lake an hour's drive from Los Angeles was searched by dozens of divers working in waters with little visibility, with help above from helicopters, drones and all-terrain vehicles.

Rivera played singing cheerleader Santana Lopez for six seasons on the Fox musical-comedy "Glee."

If she is declared dead, she will become the third major cast member from the show to die in their 30s.

Cory Monteith, one of the show's leads, died at 31 in 2013 from a toxic mix of alcohol and heroin.

And co-star Mark Salling, who Rivera dated at one point, killed himself in 2018 at age 35 after pleading guilty to child pornography charges.

Rivera had experience boating on the lake in Los Padres National Forest, authorities said.

Surveillance video shows Rivera and her son, Josey Hollis Dorsey, leaving on the rented boat.

When the boat failed to return, its vendor found the vessel drifting in the northern end of the lake late Wednesday afternoon with the boy asleep on board. He told investigators that he and his mother had been swimming and he got back into the boat but she didn't, according to a sheriff's office statement.

The boy was wearing a life vest, and another life jacket was found in the boat along with Rivera's purse and identification.

Rivera is believed to have drowned "in what appears to be a tragic accident," the statement said.

The boy, Rivera's son from her marriage to actor Ryan Dorsey, was safe and healthy and with family members, authorities said. The couple finalized their divorce in June 2018 after nearly four years of marriage.

The most recent tweet on Rivera's account, from July 7, read "just the two of us" along with a photo of her and her son.