Police in Cancún are searching for the driver of an SUV after a 78-year-old tourist was struck and killed on Boulevard Kukulcán. Witnesses described a chaotic scene in the hotel zone as traffic stopped and family members pleaded for help. Authorities have begun to pull video from city cameras and say the path of the vehicle may already be mapped. What the footage shows, where the impact occurred, and what investigators learned from relatives and first responders are part of our reporting for subscribers . . .