Naya Rivera, 33, was declared dead after officials found her body in Lake Piru in California. The cast of Glee suffered a terrible loss on the same day as co-star Cory Monteith's seventh death anniversary.

Authorities had been looking for Rivera since Wednesday, July 8, after she went missing boating with her 4-year-old son, Josey. He told police that the actress had gone swimming but never returned.

Rivera is known for playing the cheerleader Santana Lopez in the popular musical TV series Glee, where she was part of the cast from 2009 to the show's finale in 2015. She is of Puerto Rican, African American, and German descent.

The Day She Went Missing Was Nothing Out of the Ordinary

Police said Rivera and Josey rented their boat at around 1 p.m. in the Los Padres National Forest. She was wearing white shorts, a white hat, and carrying a large bag, an eyewitness account said.

They were assisted into the boat by attendants. "It was a beautiful day. It was comfortable weather, and there were other pontoon boats in the water and even a water skier," the eyewitness tells ET Online.

According to the report, she looked "like any other mother" who was on an outing to enjoy the day.

The sheriff's office released a video of Rivera and her son arriving at the lake, renting the boat, and going off the dock. This is believed to be the last image of the actress before she went missing.

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She May Have Died Saving Her Son

Rivera first went missing after her son was found alone on the pontoon boat they rented. The police were alerted with a 911 call saying the child's mother was "nowhere to be found."

Ventura County Sheriff Bill Ayub said the lake could sometimes have strong currents in the afternoon.

According to Ayub, Josey said he saw his mother "disappear beneath the water." The police believed the actress pushed her son back into the boat but did not manage to board the boat herself.

"We believe that she mustered enough energy to get her son back on the boat, but not enough to save herself," authorities said in a Variety article.

A Massive Search Happened

What was initially a search and rescue operation moved to a "search and recovery operation" after police could not find any trace of Rivera.

They used equipment like side-scanning sonar, divers, sniffer dogs, helicopters, and remote-operated submarine vehicles equipped with a camera.

Footage of the underwater search was shared. It showed low visibility on the floor on the lake.

Police believed Rivera might have been "entangled in something" under the water. They closed the lake to the public as the search went on.

There's No Sign of Suicide or Foul Play

When the body was first found, Ayub said they were "confident" the body they found was Rivera based on the body's location, physical characteristics, clothing, and physical condition. They said no other missing persons in the area, reported ET Online.

The body was found at 9 a.m. in the northeastern part of the lake near the water's surface. The area is about 35 to 60 feet deep.

The area had a heavy brush and trees 15 to 20 feet high, so it was hard to find the body.

Authorities did not find signs of foul play, reported BBC. But an autopsy will be done at a later time.

Rivera's family was showered with condolences from fans and the actress' co-stars.

"Rest sweet, Naya. What a force you were," Rivera's Glee co-star Jane Lynch wrote on Twitter.

Josh Sussman, another Glee co-star, tweeted: "Naya, you will be missed so much."

Authorities were trying to give the family closure from the beginning of their search, and this, which we hoped never happened, gave them a tragic close.

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