Massacres of the Aurora scale happen monthly in Mexico. They happen on the streets. They happen neither because of guns from the US, nor due to certifiable PhD program dropouts. Automatic weapons are NOT legally entering Mexico from the US, unless those guns come from a program run by Eric Holder. And that's not legal, either.
You might consider giving honest Mexican citizens the right to defend themselves, rather than Tweeting this sort of BS:
Mexican President Felipe Calderon condemned U.S. gun laws as "mistaken" and urged Washington to review them after a shooter killed 12 people and injured more than 50 others at a U.S. movie theater on Friday...55,000? That's more than Chicago in a decade, so I'd appreciate a comment on the effectiveness of Mexican gun prohibition. If it's really working well there I might change my mind. You know, if between 2002 and 2007 there were 100,000 people killed, and it's almost been halved.
Fighting among the [Mexican drug] cartels and their clashes with the state have killed more than 55,000 people since 2007.
We don't need your advice Mr. Calderon. Your citizens are disarmed and unable to defend themselves. THEY need the Second Amendment.
As to guns used against innocents in your corrupt state, it's you who is mistaken. You'll find educational material here.