An autopsy has been unable to determine the cause of actor Chris Penn's death, after his body was found in California.
Penn's body was found at his California home on Tuesday
A Los Angeles coroner has ordered a blood toxicology test on the actor, who starred in Reservoir Dogs and was the brother of actor Sean Penn.
The toxicology test was "normal procedure for someone who's 40 and has not seen their doctor," coroner's spokeswoman Brenda Shafer said.
His latest movie was shown at the Sundance Film Festival on Wednesday.
'No foul play'
Penn's body was discovered by a housekeeper at his home in Santa Monica, Los Angeles, on Tuesday.
He weighed more than 300lb (21st) and had a history of drug abuse, said Los Angeles County Coroner's Office spokesman Craig Harvey.
The autopsy revealed no sign of foul play or suicide, pointing instead to natural or accidental causes of death, Mr Harvey said.
"We don't know how recent, or if any drug use occurred up to the time of his death," he added. "We just need to rule it out before we close the case."
Penn played Nice Guy Eddie Cabot in director Quentin Tarantino's Reservoir Dogs as well as appearing in movies Short Cuts, Mulholland Falls, Murder by Numbers and Starsky and Hutch.
The autopsy was conducted hours before his latest movie, The Darwin Awards, premiered at the Sundance festival.
He plays a hunter who fakes the theft of his truck to collect insurance money in the comedy adventure, which also stars Winona Ryder, Joseph Fiennes and David Arquette.
Ryder paid tribute to Penn at the Wednesday screening, calling him a master character actor who would be sorely missed by friends and colleagues.
"I really hope people go back and watch his movies. He was such a fantastic actor," she said. "He's not just Sean's little brother. He was Chris Penn."
Darwin Awards director Finn Taylor said Penn "gave an incredible performance in the film that's going to make a lot of people laugh for a years to come".