After completing an autopsy, the Ventura County Medical Examiner confirmed the identity of Rivera's body and has determined her cause of death to be drowning and the manner of death is accident.
"The autopsy findings are consistent with a drowning and the condition of the body is consistent with the time that she was submerged," the report obtained by E! News stated. "No traumatic injuries or disease processes were identified at autopsy. There is no indication from the investigation or examination that drugs or alcohol played a role."
The 33-year-old actress went missing on July 8 while boating with her 4-year-old son Josey at California's Lake Piru. An investigation was launched to find Rivera after authorities found her son alone on a boat in the middle of the lake, which is located about 50 miles north of Los Angeles.
On Monday, July 13, the Ventura County Sheriff's department said that a body had been found at Lake Piru. Hours later, Ventura County Sheriff Bill Ayub said that authorities are "confident" that the body is Rivera's, and that the body was discovered floating at the surface of the lake by personnel searching by boat early Monday morning.
Ayub said in Monday's press conference, "Based on the location where the body was found, physical characteristics of the body, clothing found of the body and the physical condition of the body, as well as the absence of any other persons reported in the area, we are confident the body we found is that of Naya Rivera."
Amid the investigation, authorities spoke to Rivera's son Josey, who she shares with ex Ryan Dorsey. From speaking with Josey, authorities were able to determine that the mother and son went swimming in the lake on July 8 and that "her son described being helped into the boat by Naya, who boosted him on to the deck from behind. He told investigators that he looked back and saw her disappear under the surface of the water."
"There are a lot of currents on the lake that appear particularly in the afternoon," Ayub went on to explain. "We believe it was mid-afternoon when she disappeared, 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."
Rivera's friends, fans and former Glee co-stars have been sharing moving tributes for the beloved star. In a touching post on Instagram Tuesday, July 14, Dianna Agron reflected on her time with Rivera on the Glee set.
"Naya and I fell into stride with such ease, she was my first friend and ally on our show," Agron wrote. "In the pilot, our characters came and went with such swiftness. Our enthusiasm brimmed with all of the unknown. We tried to grasp what the other cast members must be feeling as we were working in such separate manners. We dared to dream. What if this show worked? Wouldn't that be something? Something was brimming, it was palpable. And thank god it worked. Naya's magnetic talent was going to be unleashed, we just didn't know it yet."
"I've been revisiting Naya's performances on our show and it has brought me great joy. To work with her was a gift," Agron continued. "There was a great deal to absorb - her work ethic, her fearlessness, her talent - supreme. Naya had a laugh that would envelop you and hold you captive. She was mesmerizing. That twinkle in her eye, her luminous smile. Naya lead with truth, humor, wit. I loved her for all of these reasons. "
Agron concluded her post with, "I cannot make sense of this tremendous loss. I will hold onto her and these memories for the rest of time, alongside our Glee family. Please hold space for her, her family, her beautiful boy. In absolute, loving memory."