The Glee star was buried at Forest Lawn Memorial Park in Los Angeles on July 24, according to her death certificate, which was obtained by PEOPLE.
The document, filed in Ventura County, California, confirms that Rivera’s cause of death was “drowning” and states that she died within a matter of “[minutes].”
It also notes that there were no other significant conditions that contributed to her death.
Rivera was confirmed dead at age 33 on July 13 — five days after she disappeared during a trip to Ventura County’s Lake Piru. She was reported missing after renting a pontoon boat with her 4-year-old son, Josey Dorsey.
When the boat became overdue for return after its three-hour rental, staff found it at the north side of the lake, with Josey wearing a life jacket, sleeping alone on board. An adult life jacket, believed to be the one provided to Rivera, was still on the boat.
After Josey was found, he told investigators that he and his mother had been swimming in the lake, and he got back in the boat, but she did not.
One day later, police announced she was presumed dead maintaining they considered her disappearance to be “a horrible accident.”
On July 14, the Ventura County Medical Examiner announced that an autopsy had been conducted and revealed Rivera’s cause of death as drowning and the manner of her death was an accident.