Chris Penn, the brother of Sean Penn, was found dead at his Santa Monica residence, authorities said.
Police discovered the actor's body around 4pm local time yesterday, Lt. Frank Fabrega said. Police said he was 40 years old. There were no obvious signs of foul play, Fabrega said.
Post-mortem results were pending.
"The Penn family would appreciate the media's respect of their privacy during this difficult time," Mara Buxbaum, Sean Penn's publicist, said in a statement.
Penn's body was discovered in a bed inside the residence, located in a four-storey condominium complex near the beach, said Capt. Ed Winter of the county coroner's office. Authorities were called to the condominium complex by Penn's housekeeper, Winter said.
Last night, actor Martin Sheen left the condominium complex from a rear exit with two older women but did not comment.
Chris Penn's credits included Mulholland Falls, Rumble Fish, All the Right Moves, Footloose and Rush Hour.
He also played Nice Guy Eddie Cabot in the 1992 Quentin Tarantino crime drama Reservoir Dogs.
His late father, Leo Penn, directed television shows. His mother, Eileen Ryan, is an actress whose credits include I Am Sam, Magnolia and Parenthood. Another brother is musician Michael Penn.
Chris Penn's latest film, The Darwin Awards, was scheduled to premiere today at the Sundance Film Festival.Reuse content