The Mark Kilroy case is a chilling true crime story involving a University of Texas student who disappeared during spring break in Matamoros, Mexico, in 1989. Kilroy was later found to have been kidnapped and murdered by a drug cult led by Adolfo Constanzo, which practiced ritualistic human sacrifices as part of their belief system. His death shocked both the U.S. and Mexico, leading to an intense cross-border investigation that exposed a gruesome network of occult crime tied to drug trafficking.