It was a mystery that perplexed investigators in Orange County, North Carolina for years. In September of 1998, a grass-cutting crew discovered skeletal remains under a billboard off Interstate 85 in Mebane. The clothing found with the remains offered clues that the body belonged to that of a young boy who had not yet reached puberty. He had dark, straight brown hair and was initially thought to have been Hispanic and possibly a migrant worker. For years, no one knew who the boy was. Thanks to the dogged determination of an Orange County sheriff’s investigator named Tim Horne, the boy, Robert “Bobby” Adam Whitt, has finally been identified and his murderer brought to…