Sean Mattson - Express-News
The killings came amid unrelenting drug gang violence reported to have claimed more than 700 in the troubled border city of 1.3 million people this year.
But the armed forces have struggled, and more than 2,500 have died in drug-related violence across the country this year.
Police did not offer a motive for the killings, but the shooting had all the hallmarks of gangland slayings preferred by drug gangs to intimidate and settle scores.
The gunmen had a list of targets, according to a witness interviewed by the newspaper, which reported an evangelical minister was among the victims and a pregnant woman was among those wounded in the attack.