Malcolm-Jamal Warner, the actor and musician who rose to fame as a teenager playing Theo Huxtable on NBC’s groundbreaking sitcom “The Cosby Show,” has died at the age of 54. Warner reportedly drowned on Sunday while swimming near Limón on the Caribbean coast of Costa Rica, according to the country’s Judicial Investigation Department. Authorities said he appeared to have been caught in a strong current. Bystanders attempted to rescue him but were unsuccessful.