An American facing drug charges in Arizona is a "person of interest" to U.S. and Mexican authorities investigating the deaths of four Americans in Tijuana, Mexico.
Still, authorities say that since 22-year-old Ernesto Murguia Ochoa hasn't been found, they worry that he also may have been a fifth victim.
Luis Gamez Junior, 22, Brianna Hernandez Aguilera, 19, Carmen Ramos-Chavez, 20, and Oscar Garcia Cota, 23, said they were headed for a night of partying across the border only to be found strangled, stabbed and beaten a few days later.
Mexican prosecutors say the victims had been bound and tortured before being left in a van in a dusty slum on the outskirts of Tijuana.
Murguia rented a house in Tijuana where authorities found the ID cards of the dead Americans and walls stained with blood.
Murguia was charged in September in Phoenix with conspiracy to sell or transport marijuana, illegal control of a criminal enterprise and transportation of narcotics. The 54-count indictment names 29 other defendants.