Actor Paul Rodriguez's Friend Dies in His Home, No Foul Play Suspected

Actor-comedian Paul Rodriguez's best friend died in his L.A.-area home Thursday ... and cops are saying the death looks natural, with nothing nefarious suspected at this point.

We spoke with Paul ... who tells us his longtime friend Donald Serrato had just sold his house in Torrance and was moving to Montana -- but, before he moved, he needed a place to stay for a few days.

PR gave his friend a place to stay, and -- this morning -- he left around 6 AM to go work on a movie. He called Serrato around noon to see if he wanted to grab lunch, but received no response.

Since he couldn't get in touch with Donald, Paul called his girlfriend, who went to check on him ... and found him in bed, turned completely blue.

Paul says Donald's GF and her friend called 911, and they tried to perform CPR on him with the help of the operator ... but, he was already dead.

Rodriguez says Serrato was a heavy drinker and smoker who was dealing with the loss of a couple family members ... all of which, Rodriguez believes may have played a role in his death.

Law enforcement sources confirm ... they responded to a call about a man not breathing just after 12:30 PM, arriving at Rodriguez's home shortly after. Serrato was pronounced dead at the scene.

We're told there is no foul play or drugs suspected ... and, this appears to be a natural death.

Paul himself has had a long career in the film industry ... appearing in big projects like Clint Eastwood's "Blood Work," "The Golden Girls," "The Twilight Zone," "Sandy Wexler," "Clifford the Big Red Dog," "King of the Hill," "Grand Slam" and more. Perhaps his most credit -- he's the father of famed skateboarder Paul "P-Rod" Rodriguez Jr.

Serrato was 50.