McKinney police are searching for the driver that struck and killed a 14-year-old boy, then drove off Saturday evening. The hit-and-run incident happened on the intersection of Lake Forest and Highlands Drive at about 6:14 p.m. Police said the child was hit by a vehicle described as dark-colored, four-door sedan, which left the scene after the incident. The car may have front end damage and damage on the passenger side mirror.