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Sylvester Stallone's 36-year-old son Sage Moonblood Stallone, who appeared with his father in Rocky V
, was found dead in his Los Angeles home Friday.
"Sylvester Stallone is devastated and grief-stricken over the sudden loss of his son Sage Stallone," says a rep for the actor.
"His compassion and thoughts are with Sage's mother, Sasha. Sage was a very talented and wonderful young man, his loss will be felt forever."
Police officers were called to the house at 2:17 p.m. and discovered the body. There were no signs of foul play or forced entry.
"It sounds like a terrible tragedy. He was way too young to die," LAPD Commander Andrew Smith tells PEOPLE.
He adds that reports that Sage died from a prescription overdose are premature.
"It could have been a heart attack or a stroke," he says, adding the coroner's office will likely spend several weeks on a toxicology report before it can reach any such conclusion.
Sage's attorney George Braunstein tells PEOPLE that Sage's housekeeper initially found him dead.
"(Sage) was full of life, a wonderful, loving person," says Braunstein. "The last time I talked to him a few days ago he was saying he was getting married, he had a lot of things he was working on and seemed very enthusiastic. There was no indication there was any problem."
Sage, who Sylvester, 66, had with ex-wife Sasha Czack, was best known for appearing alongside his father in Rocky V
, playing son Robert Balboa. He also appeared with his dad in 1996's Daylight.
The New York Post
first reported Sage's death.