Sylvester Stallone hires famed PI to investigate son's death

Sylvester Stallone has called in a private investigator to figure out how his son Sage died and what lead up to the tragedy ... TMZ has learned.

We've learned famed P.I. Scott Ross -- who was the lead investigator in the Michael Jackson molestation case and the Chris Brown/Rihanna battery case -- met Tuesday at Stallone's home with Sly, his brother Frank, and an official from the L.A. County Coroner's Office. Sources tell us they discussed Sage Stallone's death and the status of the investigation.

Sylvester Stallone - I'm grief stricken

Sylvester Stallone tells TMZ he is devastated by the death of his son Sage Stallone and wants "the speculation and questionable reporting" to stop.

Stallone -- who gave us this picture of him with Sage taken in 1991 by famed photog Bruce Weber -- says, "When a parent loses a child there is no greater pain. Therefore I am imploring people to respect my talented son's memory and feel compassion for his loving mother Sasha."

Sly goes on to say, "This agonizing loss will be felt for the rest of our lives," adding, "Sage was our first child and the center of our universe and I am humbly begging for all to have my son's memory in full left in peace."

Sylvester Stallone's son found dead in LA

Sylvester Stallone's 36-year-old son, Sage Moonblood Stallone, was found dead in his Los Angeles home Friday, police said.

TMZ.com reported the cause was an apparent overdose on pills. But a rep for the LAPD told the Daily News it was too early to determine the exact cause of death.

Cops found the body about 2:15 p.m. after a worried caller reported Sage could not be reached, police said. There were no signs of forced entry and no foul play was immediately suspected.

Sylvester Stallone —who had been at San Diego Comic-Con promoting his upcoming film,“Expendables 2” — “is devastated and grief-stricken,” according to his rep, Michelle Bega. “Sage was a very talented and wonderful young man. His loss will be felt forever,” Bega said. Sage’s mother, Sasha Czack, was also grieving over the loss of her son.

“Everybody’s devastated,” said Sage’s longtime lawyer, George Braunstein. “He was just a wonderful, wonderful person. It’s a terrible tragedy.” The younger Stallone has a handful of movie credits — most recently Vincent Gallo’s 2010 flick “Promises Written in Water.” More recently, he co-founded Grindhouse Releasing, a company that restores exploitation films.