America's outgoing CIA Director, Michael Hayden, says violence in Mexico will pose the second greatest threat to U.S. security next year, right after Al Qaeda. Focused on the drugs and migrants who flow into the U.S., the flow of weapons into Mexico is often overshadowed. Moreover, border control is much weaker going south than going north. In an unsuccessful cartel rescue attempt, Mexican authoritie3s captured 540 assault rifles, more than 500,000 rounds of ammunition, 150 grenades, 14 cartridges of dynamite, 98 fragmentation grenades, 67 bulletproof vests, seven Barrett .50-caliber sniper rifles and a Light Anti Tank (LAW) rocket.