Boston Marathon Attack Map: Before and After Photos [Graphic]

Be advised: some graphic photos below.

First Explosion Site







Second Explosion Site









Fox News Catherine Herridge reports that a 20-year old Saudi national -- in the U.S. on a student visa -- is a "person of interest", hospitalized with severe burns. Former Secret Service Agent Dan Bongino noted that the hospital area is being guarded by a Special Weapons Team, which would indicate more than a passing interest in the individual.

In 2012, 20,677 student visas were granted to Saudi citizens.