CULIACÁN, Mexico—Even Jesús Malverde, the patron saint of drug traffickers, has fallen victim to the vicious turf war ripping apart Mexico’s biggest producer and smuggler of fentanyl.

there is a shrine to Jesus Malverde and on the third of every month his followers come to commemorate his death. Ivonne Valdez Pulido is in charge of the Malverde shrine: "In the beginning about ...