TAXCO, Mexico – Many times, the victims in Mexico’s drug war simply disappear. Just a few miles outside this quaint tourist town filled with silver jewelry shops, Mexican authorities discovered where some ended up.

For months, maybe for years, feuding drug mafias have unloaded their bound-and-gagged victims from pickup trucks and car trunks and thrown them down a deep, dark hole. It is one of the most macabre spectacles in a drug war that each week brings news of greater barbarities.

For the past year, locals here reported rumors of strange vehicles on the road at night. And in May, the Mexican military arrested some gunmen who revealed under pressure the existence of a mass grave, which is the largest ever found in Mexico.