The Mystery of What Motivated the Tsarnaev Brothers To Act

Search For Home Led Suspect To Land Marred by Strife by David M. Herszenhorn and Andrew Roth.  The New York Times.  April, 21, 2013.

Boston Marathon Bombings:  Turn to Religion Split Bomb Suspects Tamerlan and Dzhokhar Tsarnaev's Home by Alan Cullison, Paul Sonene, Anton Troianovski, and David George-Cosh.  The Wall Street Journal.  April 22, 2013.

These two excellent overviews provide religious, cultural, and political context for the actions of the accused Boston Marathon bombers.  The question remains however of what in the final analysis, motivated the brothers to take action.  Here are some questions for consideration focusing on the brothers' US citizenship applications:

Could granting of citizenship to Dzhokhar while consigning Tamerlan to "pending" status be at least part of that motivation?

Could Dzhokhar have viewed the "pending" status given to his brother as a humiliation to the person he so deeply admired?

Could Dzhokhar have viewed his own successful application in light of his brother's pending status as more an insult to his brother than a personal honor or attainment for himself?

Could Dzhokhar have been subject to taunts from his brother for attaining citizenship while he was delayed in "pending" status?

Could Tamerlan have used his brother's  citizenship as a tool to coerce loyalty from Dzhokhar?  "Do you love me or do you love this country which questions my access to citizenship?"

Could Tamerlan used this reasoning to coerce Dzhokhar into actions that were out of character, the character as described by his classmates?

While these questions are worth consideration in the final analysis there can probably be no explanation for such an event as the Boston Marathon massacre.  We would probably not be able to understand an explanation  even if we were to hear it.