Gunmen killed 16 people, including a police chief, in a spate of separate shootouts across Mexico, which is grappling with a spike in drug-related violence, local officials said. Six of the murder victims in Culiacan were inside a car repair shop, while three others were killed outside, the state attorney's office said. Reporters said the three victims outside the shop were police officers who rushed to the scene of the gunfire. Four more men were found shot to death in Guadalupe, Calvo and Juarez, the Chihuahua state officials said.