How mapping America's "firearm ecosystem" could help lead to gun violence solutions

On April 16, 2007, about a year after Maurizio Porfiri moved to New York City to start his career as an engineering professor at New York University, one of his undergraduate students rushed into his office, desperate, saying, "Professor I'm really sorry." 

At first, he didn't know what was going on, but then Porfiri saw on the news there had been a mass shooting at Norris Hall, Virginia Tech's engineering science and mechanics building, where he had received his doctorate and spent seven years studying in the department.

"I started calling people, but no one would reply. It was a disaster," Porfiri told CBS News. Porfiri was a teaching assistant for Liviu Librescu, the engineering professor who blocked the door to his classroom to allow students to escape out the window. Another of the professors in his Ph.D. committee was also among the 32 people killed that day, as were other colleagues and classmates who helped Porfiri become who he is "personally and professionally," he said.