CNN reports that the body of Rev. Gregorio Lopez was found shot dead on Christmas Day after being kidnapped in Mexico’s south-western drug cartel state Guerrero.

The motive for the killing remains unclear, but he is the third priest to be killed in the state this year.

“A friend of the priest told local media that Father Lopez was kidnapped after he accused drug gang Guerreros Unidos of the abduction and alleged murder of 43 students in September,” said CNN.