At first I thought, oh great, another turrurrist attack. But we haven't found out who the hell did it yet. So it's not a foreign threat like everyone assumes it is. Almost every single foreign born threat that is blowing shit up in the name of Taliban/Al-Qaeda/Islam almost always gets caught or openly takes credit for the deed. Why? For recognition, pride, make their faction seem superior in some twisted manner. But they haven't come out to accept their glory yet. So it's probably just another home born terrorist. Like the Newtown shooter, Batman Movie Shooter, Virginia Tech Shooter, Columbine Shooters, Oklahoma Bomber, etc. And yes they're all god damn terrorists too. He or she is probably pissed off that gun control is occurring, realized the Newtown incident caused the movement, saw the marathon was dedicated to the Newtown victims, thought the message would get across if he blew them up.