Heavily armed gunmen staged a series of surprise attacks against municipal police forces in this tense border city, killing seven and wounding three in brazen assaults that shattered a four-month period of relative calm.
Six police officers and an auxiliary officer died within a 45-minute span late Monday in ambushes at a hillside substation, on busy streets and outside an OXXO mini-mart, where four were killed in a hail of bullets, including one who tried to fight back.
