That is the question everyone wants to know when it comes to the Boston bombing suspects.
The other big question is, of course, did they get help? Since 9/11, American intelligence has been able to shut down Al-Qaeda-backed plots on our soil, but the lone wolf terrorist remains a threat.
The murders of 13 people by Major Nidal Malik Hasan in 2009 at ForT Hood is just one example.
The horror of the Boston bombings lies in part because the two young men who were embraced by their new country, betrayed it. It remains to be seen if 19-year-old Dzhokar Tsarnaev, who while gravely wounded was willing to engage police in a second firefight, will offer up an explanation.
It is also unclear whether this young man will be able to offer a full insight into his brother’s mindset. Given American intelligence successes in recent years there is reason to be hopeful we will find out if they acted alone, but the elusive why is the explanation we all really need.