James V Grimaldi

Arizona's gun laws, among the most lenient in the country, allowed Jared Lee Loughner to conceal and carry his firearm without a permit, explains Washington Post reporter James Grimaldi, who wrote a piece Sunday about Arizona's lax gun laws and Saturday's Tuscon shooting rampage.

Since 2006, more than 60,000 of the weapons used in Mexican crimes have been traced back to the United States. Washington Post investigative reporter James Grimaldi explains how a team of reporters uncovered the names of the top 12 U.S. dealers of guns traced to Mexico.