Actress, 33, went missing five days ago. Her son, 4, told authorities she boosted him back on the deck of their rented boat before disappearing under the water
The actress went missing last Tuesday at Lake Piru, where she visited with her four-year-old son Josey.
Josey was found safe in a boat that he had been on with his mum prior to her disappearance.
Police confirmed on Monday that they had found a body in the search for Ms Rivera and on Monday evening confirmation followed that the body was that of the Glee star.
Investigators believe that the mum-of-one was able to save her son from the water at the lake, but she was unable to then save herself.
Ventura County Sheriff, Bill Ayub, said: ‘It would be speculation to say at this point there are a lot of currents in the lake that appear particularly in the afternoon.
‘We believe it was mid-afternoon when she disappeared, the idea perhaps being that the boat started drifting. It was unanchored.
‘She mustered enough energy to get her son back on the boat but not enough energy to save herself.
‘We know from speaking with her son that he and Naya swam in the lake at some point in the day.
‘He told investigators that he looked back and saw her disappear under the surface of the water.
‘The young boy was wearing a life vest when he was found, he was wrapped in a towel. An adult-sized life vest was found on the boat.’
Police said that they have ruled out any form of foul play or suicide as part of the investigation into the incident.