They are both.
The Boston Bombers were and are terrorists, but they are no different than the Columbine killers or Adam Lanza.
Thankfully, the Boston Bombers did not have a body count as high as Adam Lanza or the Columbine killers.
“Thankfully, the Boston Bombers did not have a body count as high as Adam Lanza or the Columbine killers.”
Not for lack of trying.