A city in northwestern Sonora has again been the site of troubling violence.

On Friday evening, a police officer assigned to protect the mayor of Caborca was killed, according to state security officials. Alvaro Bracamonte, a high-ranking state official, told local media that security forces would be reinforced in the area in response to that incident, as well as the recent arrest in Hermosillo of a man suspected of being a key player in human trafficking in northwest Sonora.

For several years, Caborca has been an epicenter of violence in the state. Through the end of September, 117 murder cases had been registered in the city, the highest figure for that period since at least 2015, according to the most recent federal data.