Mexico gangs threaten to behead DEA agents

A spray-painted sign threatening death for U.S. Drug Enforcement Administration agents was found Friday next to a school in a northern Mexico state capital, officials said. Addressed with profanity to "Gringos (D.E.A.)," the unsigned graffiti warned: "We know where you are and we know who you are and where you go. We are going to chop off your (expletive) heads."