Former Glee actress Naya Rivera has gone missing after a trip to a lake in Southern California.
A search operation was launched after her four-year-old son was reportedly found alone on a rented boat at Lake Piru.
The search will resume "at first light" on Thursday, the sheriff's department said.
Rivera, 33, is best known for playing Santana Lopez on musical comedy series Glee.
According to local reports quoting the sheriff's department, Rivera rented a boat at Lake Piru at about 1pm local time.
The alarm was raised and a search operation launched using helicopters, drones and dive teams, police said.
On Tuesday, Rivera tweeted a picture of her and the boy together, which was captioned: "Just the two of us."
Rivera's child was spotted by another boater three hours after the actress had taken the boat, CBS Los Angeles reports, quoting the sheriff's office.
It says the boy told investigators that he and his mother were swimming - but the she never got back into the boat.
Rivera earned significant success starring as high school cheerleader Santana in Glee and the California-born star followed it up with her feature film debut in 2014 horror film At The Devil's Door.
She later had a role in the Lifetime TV series Devious Maids.
Rivera was engaged to the rapper Big Sean in October 2013 but they ended their relationship in April 2014.
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She then began dating actor Ryan Dorsey and they got married in Mexico in July that year.
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The couple welcomed their first child, Josey Hollis, in September 2015. Rivera filed for a divorce after two years of marriage but later called off the separation.
The couple finalised their divorce in June 2018.
After news she was missing broke, Rivera's former Glee co-star Harry Shum Jr tweeted: "Praying."
