Copyright © 2022, Los Angeles Times | | | | After hearing that her 44-year-old son had been in downtown Tijuana, Guadalupe Aragón Sosa went searching for him.She gave police a sample of her DNA, but they said they found no hits when they checked it against a database of unidentified bodies. She spent hours at the local morgue, flipping through black-and-white photographs of unclaimed corpses, but her Carlos was not among them.Advertisement She scoured fields and garbage dumps on the outskirts of town where local thugs were known to bury their victims, probing the soil with a metal rod in...…Copyright © 2022, Los Angeles Times | | | | After hearing that her 44-year-old son had been in downtown Tijuana, Guadalupe Aragón Sosa went searching for him.She gave police a sample of her DNA, but they said they found no hits when they checked it against a database of unidentified bodies. She spent hours at the local morgue, flipping through black-and-white photographs of unclaimed corpses, but her Carlos was not among them.Advertisement She scoured fields and garbage dumps on the outskirts of town where local thugs were known to bury their victims, probing the soil with a metal rod in...WW…