An investigator says a 13-year-old Alabama girl with special needs was beheaded last month after watching her grandmother be fatally stabbed in a cemetery.

The details emerged in a Madison County court during a preliminary hearing for 26-year-old Yoni Aguilar.

Aguilar and 34-year-old Israel Palomino are charged with two counts each of capital murder in the June slayings of 49-year-old Oralia Mendoza, 49, and her granddaughter, Mariah Lopez.

Authorities said Mendoza was associated with the Sinaloa cartel, one of the world’s most powerful drug-trafficking organizations.

Aguilar told investigators he, Mendoza, Palomino and another woman traveled to Georgia in early June to pick up a kilo of methamphetamine. The arrangement reportedly turned awry when Palomino became suspicious of Mendoza and the other woman because of their cartel connections. Aguilar, who was Mendoza’s live-in boyfriend, said he thought he was being set up.

A couple days later, Palomino and Aguilar picked up Mendoza and her granddaughter from Mendoza’s house, saying they would take them “somewhere safe.” The men reportedly drove Mendoza and her granddaughter to a cemetery and Mendoza was fatally stabbed following an argument over the drug buy.

Aguilar told investigators Palomino then forced him to kill the girl in a secluded area because she was a witness, police said.