Actress Naya Rivera is missing and presumed dead in a Southern California lake, according to authorities, after officials found her 4-year-old son floating alone on their rented boat on Wednesday afternoon.

The Ventura County Sheriff’s Office confirmed late Wednesday that a “possible drowning victim” at Lake Piru was Rivera, 33, best known for her breakout role in the TV series “Glee.”

The sheriff’s office resumed its search-and-rescue mission “at first light” on Thursday, when officer Chris Dyer later confirmed at a news conference that it had turned into a search-and-recovery effort. He said the office is presuming Rivera drowned in the lake.

There’s no signs of foul play, no signs of anything that went wrong besides a tragic accident,” Dyer added. “Switching that mode to a search-and-recovery mode, like I said, does not change the efforts and does not change the gusto, what we push forward with the search operation. The goal is still to bring Ms. Rivera home to her family, so they can have some closure.”