LOS ANGELES  — The search to find “Glee” TV show star Naya Rivera in a Southern California lake resumed on Sunday, authorities said.

The Ventura County Sheriff’s Office said in a tweet Sunday morning that the search would include cabins and outbuildings in the surrounding area. In another tweet, they warned the "terrain around the lake is very steep and rugged," adding they didn't want to have to rescue anyone intent on searching for Rivera.

Authorities said Thursday they believe Rivera, 33, drowned in the lake. Her 4-year-old son was found alone in a rented boat.

The boy, who was found asleep and wearing a life vest late Wednesday afternoon, told investigators that he and his mother went swimming and he got back on the boat, but “his mom never made it out of the water,” Sheriff’s Sgt. Kevin Donoghue said.

Rivera began acting at a young age, but she rose to national attention playing a lesbian teen on “Glee,” which aired from 2009 until 2015 on Fox.

Rivera was engaged to rapper Big Sean in 2013, but their relationship ended a year later. The pair met on Twitter and collaborated musically, with the rapper appearing on Rivera’s debut single “Sorry.” She married Dorsey a few months later.