Mr. Warner, who played the only son of Bill Cosby’s character on the beloved 1980s sitcom, drowned in Costa Rica.

New details about the circumstances of “Cosby Show” star Malcolm-Jamal Warner’s death have emerged.

“Two people who were there at the location went in with a surfboard and a boogie board to help rescue [Malcolm and his daughter] caught in the current,” Costa Rica’s Atlantic head of Tourist Police, E...