Before dawn, an elementary school principal in the capital of Mexico's Sinaloa state checks various chats on his phone for word of shootouts or other incidents. If there’s danger, he sends a message to his students’ parents suspending classes.
It isn’t the only new routine in Culiacan, a city of 1 million residents that for the past six months has been the battlefield for the two main factions of the Sinaloa drug cartel.
