MEXICO CITY — Gunmen ambushed the director of state police in the cartel-plagued northern Mexico state of Sinaloa and killed him Monday, authorities said.

State Public Safety Secretary Cristóbal Castañeda said Joel Ernesto Soto was found dead in his bullet-riddled car on a highway near the state capital, Culiacan. Castañeda called it “a cowardly attack.”

A bodyguard who was with Soto was missing.

Soto was an army lieutenant colonel who was on leave while heading the state police.

Sinaloa is home to the cartel of the same name. The cartel has been riven by internal differences, and is also engaged in turf battles with the Jalisco cartel.