CSI (2000) - 3x20 - Last Laugh

Grissom and Catherine investigate the murder of a despised comic who died onstage, apparently after drinking from a tainted bottle of water. The case grows more puzzling when a 15-year-old boy dies in a convenience store after drinking the same brand of water. Brass reopens a woman's accidental-death case after spotting the deceased's husband in a flashy new car with a trophy date on his arm.