Mexico's most dangerous city for police refuses to give up or negotiate with cartels

CELAYA: A dead man lay on his back in the parking lot of a convenience store in late February when journalists rolled in to the north-central Mexico city of Celaya to interview police. A spray of bullet casings and spent projectiles lay around the corpse, a sight all too common in Guanajuato state, which has Mexico’s highest number of homicides.
A policeman had been driving his wife to work on Feb. 28 when cartel gunmen — who had apparently followed from them home — opened fire on their…