PHOENIX, Arizona — As police approached a drug cartel's safe house in northwestern Mexico last May, gunmen inside poured on fire with powerful assault rifles and grenades, killing seven officers whose weapons were no match. Four more lawmen were wounded in the bloodbath and a cache of weapons was seized, including a single AK-47 assault rifle that authorities say was purchased 800 miles away at a Phoenix gun shop and smuggled into Mexico. The rifle's presence in... (GunPolicy.org)