TV highlights: Diagon Alley in Orlando gets the red carpet treatment on E!

"Dateline NBC" (NBC at 8 p.m.) investigates the nearly two-decade-long mystery behind the death of Gary Triano, a successful entrepreneur in Arizona who was killed by a car bomb in 1996. The Harry Potter franchise gets the red-carpet treatment on "Live From the Red Carpet: Diagon Alley" (E! at 8), a 30-minute special commemorating the opening of the famed and extensive cobbled wizarding shopping area at Universal Studios Florida.