Transcript for ‘Glee’ star Naya Rivera presumed dead after going missing during boat trip with son
Here's Kaylee Hartung. 911. Emergency is we have a missing person. Reporter: A nightmare comes to life on this California lake. It just seems like a tragic accident. You come out here for a great day and something bad happens. Reporter: Actress naya Rivera, now presumed dead after going missing Wednesday. Her son was found safely asleep on board their pontoon rental by another boater when they called 911 when they realized the child was alone on the boat. The 33-year-old. Sometimes I go out by myself Reporter: Made her mark on the hit TV show "Glee" as santana. I like being in glee club. It's the best part of my day, okay? Reporter: On Thursday, co-stars, friends and fans began sharing heart-felt pleas online, hoping for a miracle. Demi Lovato asking followers to pray for her to be found safe and sound. Reporter: From its first episode, "Glee" was a cultural phenomenon. Fans lovingly refer to themselves as gleeks. It was nominated for 40 emmies, winning six. "Glee" was groundbreaking for its diversity, story line. Reporter: Sadly, Rivera's disappearance isn't the first tragedy to rock the glee family. It has been marred by misfortune. Now the search for answers after the death of Cory monteith. Reporter: Seven years ago, Cory monteith died from an accidental drug overdose shortly before the fifth season. His character written into a future episode dedicated to his life. In 2018 another cast member, mark Saling, who played puck on the show. Rivera's short life had almost always been in the spotlight, nabbing her first role in "Royal family" at the age of 4. Whenever grandpa wanted to talk about you I had to leave the room. Reporter: Portraying a gay cheerleader. And the role rocketed her to fame. Naya Rivera's role was groundbreaking. Brought representation to the forefront of television. Reporter: Rivera appeared on "Rolling stone." She co-hosted "Fashion police" alongside Joan rivers. My best was the 2013 glad awards. Reporter: Most recently, she was showing off dancing skills again. The show had just been renewed for a third season by cable network STARZ!. She was very excited to join that series, which is quite an accomplishment. Oftentimes in Hollywood when characters are so famous from one particular role they can be typecast, but for naya, that didn't seem to happen. Reporter: She boasted millions of followers across Twitter and Instagram. Just one week ago the actress shared a tweet that seems prophetic. Make the most of every day. It was a calm and sunny day on the lake in southern California when Rivera rented a pontoon for an afternoon of boating and swimming with her son. Her 4-year-old was sleeping on board and Rivera nowhere to be found. A basic it timeline is that Ms. Rivera and her son came to enjoy a day on the lake. Ms. Rivera had been to the lake before, they went out for a day on the lake. Reporter: A search and rescue operation was launched Wednesday evening. But at nightfall the search was paused due to dangerous conditions. Thursday morning it was relaunched as a recovery mission. When you have the information that an adult life jacket was left on board, that the pontoon wasn't anchored, what does that lead to you believe? It's hard to draw conclusions with just that. I wish that we had a means of like, you know, really understanding what happened. But they might have innocently just been playing in the water and any number of things could have happened. Ms. Rivera could have had a medical episode of some sort. We don't know. Reporter: With Rivera still missing, questions remain as to what happened on board that led to her disappearance. Authorities struggling to piece together a timeline based on the 4-year-old's recollections. You want to try to limit the amount of trauma he's going Reporter: The boy told police the duo went for a swim but his mom did not get back on the boat. Low visibility and debris have hampered investigators. Her body may be trapped underwater. If her body is entangled in something beneath the water, it may never come back up. Reporter: By all accounts, she was a doting mom. This snap was posted of her and her son, with the caption "Just the two of us." If you look at what she said in interviews, her son seemed to be her world. Reporter: Earlier tonight in Ventura, the case still unsolved at search was called off a second day with no body found. Friends, family and fans left mourning another "Glee" life cut short. The actress once sang "If I die lay me down Reporter: What was once a loving tribute to Cory monteith, now a haunting anthem. Another life lost too soon.
This transcript has been automatically generated and may not be 100% accurate.