Josey was found safe on the boat, and Ventura County Sheriff Bill Ayub revealed in a press conference that authorities speculate that Rivera drowned after boosting her son onto the boat after a swim.
"The idea perhaps being that the boat started drifting, it was unanchored, and that she mustered enough energy to get her son back onto the boat, but not enough to save herself," he shared.
The triple threat made a colorful turn at the American Idol Top 13 Party in Los Angeles.
Rivera flashed a huge smile as she attended a Glee screening at Santa Monica High School with her co-stars Heather Morris and Dijon Talton.
The fresh-faced cutie gave off boho vibes at the Bandslam premiere in Los Angeles.
Glee castmembers Chris Colfer, Matthew Morrison, Tariq Iqbal, Jessalyn Gilsig, Jayma Mays, Jenna Ushkowitz, Rivera and Jane Lynch proudly held up their statues after winning the award for Outstanding Performance by an Ensemble in a Comedy Series at the 16th Annual Screen Actors Guild Awards in Los Angeles.
Rivera attended the Thirst Project Gala in Santa Monica, California, with her Glee co-star and onscreen love interest, Heather Morris.
The Step Up: High Water star put her best foot forward at the 62nd Annual Primetime Emmy Awards.
Rivera celebrated her 24th birthday with her Glee co-stars, including Jenna Ushkowitz, at the Bank Nightclub at the Bellagio Hotel and Casino Resort in Las Vegas.
The California native and her Glee co-star, Cory Monteith, met fans at the Skokie, Illinois, stop of the Glee LIVE Tour. Monteith died of a drug overdose on July 13, 2013, seven years to the day Rivera was pronounced dead after a five-day search for her at Lake Piru.
Royal purple looked fabulous on Rivera at the Los Angeles premiere of Glee: The 3D Concert Movie.
The Master of Disguise actress shimmered at the 18th Annual Screen Actors Guild Awards.
Rivera and her then-boyfriend, Big Sean, cozied up on the red carpet during the 42 premiere in Los Angeles. The pair got engaged in October 2013 but broke up five months later.
Rivera rocked a black tube top and sparkly pencil skirt for the Los Angeles premiere of The Hangover Part III.
The Glee gal was pretty in pink as she posed for portraits at the 2013 Giffoni Film Festival in Giffoni Valle Piana, Italy.
The "Sorry" singer looked sharp in a white jumpsuit at ELLE's 20th Annual Women in Hollywood Celebration.
Rivera stunned in a slinky LBD at the 2013 American Music Awards.
Rivera let her honey highlights shine at the Michael Kors fashion show during New York Fashion Week.
The brunette beauty kept it simple in a nude-hued slip dress and gold accessories at the Max Mara and W Magazine Cocktail Party to Honor the Women in Film at Los Angeles' Chateau Marmont.
Rivera secretly wed Ryan Dorsey in 2014. That year, the pair stepped out together at UNICEF's Dia de los Muertos Black & White Masquerade Ball at the Hollywood Forever Cemetery in Los Angeles. The pair finalized their divorce in June 2018.
The Devious Maids actress was on a silver streak at the 2015 InStyle and Warner Bros. 72nd Annual Golden Globe Awards Post-Party.
Rivera showed off her growing baby bump at the 101st Annual White House Correspondents' Association Dinner in Washington, D.C. She gave birth to her and then-husband Ryan Dorsey's only child, son Josey, that September.
The actress went for vampy vibes in a plunging plum cape dress at the 2016 InStyle and Warner Bros. 73rd Annual Golden Globe Awards Post-Party in Beverly Hills, California.
The Devious Maids star stunned in a plunging white dress at the Vanity Fair and FIAT Young Hollywood Celebration at Los Angeles' Chateau Marmont.
Rivera looked ravishing in red at the 23rd Annual Race to Erase MS Gala in Beverly Hills, California.
The California girl signed copies of her book, Sorry Not Sorry, at Barnes & Noble at The Grove in Los Angeles.
The Glee star put her uniquely fashionable spin on the Canadian tuxedo at the 2017 Teen Choice Awards.
The mom of one looked lovely in lace at Point Honors Los Angeles 2017.
Rivera looked ready to rock out at the YouTube portion of the 2018 Winter Television Critics Association Press Tour in Pasadena, California.
The Glee alum brought son Josey with her to the Los Angeles premiere of The Lego Movie 2: The Second Part.
The Mad Families actress channeled Jersey Shore in her off-the-shoulder leopard-print maxi dress at the Judy premiere in Beverly Hills, California.
Rivera's last red carpet event was in the fall of 2019, when she attended the Women's Guild Cedars-Sinai Annual Luncheon at the Regent Beverly Wilshire Hotel in Beverly Hills, California.