The L.A. County assistant coroner said there were no signs of foul play and no suicide note. But he shared signs that may point to a prescription drug overdose.
"There are some prescription bottles, however, I'm not going to detail what they were or how many," said L.A. County Assistant Coroner Ed Winter.
Sylvester Stallone was not seen at his son's home Friday night, but the entire Stallone family is dealing with the grim reality of an end to a promising life and career.
Authorities were first called to his Studio City home because his loved ones sensed trouble.
"There had been no personal contact with the deceased in the past few days," said LAPD Sgt. Jim Parker.
The LAPD and a housekeeper discovered his body inside around 2:15 p.m.
It could be weeks until an official cause of death is announced pending toxicology reports.
Just one day before, Sylvester Stallone was all smiles at Comic-Con in San Diego. His publicist says he's "devastated and grief stricken over the sudden loss of his son. His compassion and thoughts are with Sage's mother Sasha."
In a 1996 interview with ABC7's George Pennacchio, Sage Stallone said he wanted to focus on his directing instead of going into action movies. He directed the 2006 short film called "Vic," co-starring actress Carol Lynley.
"He was beautiful, he was physically beautiful, emotionally beautiful and very talented," she said.
Sage Stallone's attorney said his client was excited about life and was looking forward to getting married.
Sage Stallone made his big screen debut with his father in "Rocky V" in 1990. In 1996, he was back on screen in "Daylight," again paired up with his high profile father.
