On Saturday night, a woman named Betty Wheeler was struck and killed by a hit-and-run driver near a highway intersection in Waynesboro, Virginia.  As the scene of the crime was investigated, one piece of evidence surfaced: a car part (an air dam) that broke off upon impact (the image above).  This is when the community of commenters around the car culture blog Jalopnik took action, and may have just given the authorities some valuable information about the case.