A 13-year-old Huntsville girl was beheaded after she witnessed her grandmother assaulted with a knife and left to die on the ground in a cemetery, court testimony revealed. The grandmother was associated with the Sinaloa Cartel, a drug-trafficking organization, a Madison County sheriff's investigator testified today. Just days before Oralia Mendoza and her granddaughter, Mariah Lopez, were killed, Mendoza and three others went to pick up a batch of methamphetamine, Investigator Stacy Rutherford told a judge. After one of her drug cohorts became suspicious, the situation turned deadly.