Once his mother had helped him back on to the boat, the boy “noticed the decedent put her arm up in the air and yelled ‘help,’” the report from the Ventura County Medical Examiner says. “The decedent then disappeared in to the water.”

Authorities had previously said that Rivera had drowned accidentally after putting the boy, Josey Hollis Dorsey, back on the boat at Lake Piru northwest of Los Angeles on July 8, but had not mentioned her shouting for help.

Rivera “knew how to swim well,” the report said.

The man who rented her the pontoon boat said she declined a life vest, but he put one aboard anyway.

It revealed that the 33-year-old Rivera had previous problems with vertigo, had a recent sinus infection, and had a small amount of prescribed amphetamines in her system, but did not identify physical conditions or drugs as factors in her death.

Toxicology tests also showed she had small, therapeutic amounts of the anti-anxiety drug diazepam and the appetite suppressant phentermine in her system.

Josey, Rivera’s son with her former husband, actor Ryan Dorsey, was found sleeping and alone on the drifting boat later that afternoon.