Naya Rivera’s body was discovered Monday morning at Lake Piru, according to the Ventura County Sheriff’s Office.

Ventura County Sheriff Bill Ayub said Rivera used the last of her strength to save her 4-year-old son before dying. He said, “She mustered enough energy to get her son back onto the boat, but not enough to save herself.”

Last week, the former Glee actress and her son rented a pontoon boat at Lake Piru. Her son told rescuers that he and his mother had gone into the water to swim but she failed to get back on the boat.

Her son told investigators he then looked back and saw her disappear under the surface of the water, according to Ayub. He was found asleep on the rental pontoon boat after it was overdue for return.

Rivera was presumed dead after she went missing on Wednesday. Her body was later found floating in the northeast area of the lake where the water is between 35 and 60 feet deep on Monday, after a six-day search.

The county sheriff said investigators are “confident” the body found was Rivera. However, they have taken the body to Ventura County Coroner’s Office for identification through dental records.

Ayub said, “Her family has been at the lake everyday holding out hope and communicating with our investigators.”

Rivera is best known for her role as Santana Lopez on Glee, which quickly won critical acclaim after debuting in 2009, appearing in almost every episode of the musical-comedy-drama.

Rivera’s costars shared their condolences with her family.

Chris Colfer, who played Kurt on Glee, wrote a lengthy post on Instagram with a picture of him and Rivera. He wrote, “How can you convey all your love and respect for someone in one post? How can you summarize a decade of friendship and laughter with words alone? If you were friends with Naya Rivera, you simply can’t.”

Another costar Jane Lynch tweeted, “Rest sweet, Naya. What a force you were. Love and peace to your family.”

Rivera also appeared on the CBS sitcom “The Royal Family” and in the comedy film “The Master of Disguise.” She was married to actor Ryan Dorsey from 2014 to 2018.