MEXICO CITY—A top police official from Mexico’s Tlaxcala state has been arrested on kidnapping charges, underscoring the vast challenges that Mexican President Enrique Peña Nieto faces in his efforts to overhaul corrupt police forces and quell rampant crime.

Local prosecutors accuse Jorge López Pérez, the head of Tlaxcala’s state police, of heading a ring of officers who carried out at least four recent “express” kidnappings, which involve the abduction of victims for a few hours or days in exchange for relatively minor ransoms....