In a heated exchange with Senator Ted Cruz during a hearing earlier in the day, Mr Holder said it was not appropriate to use lethal force - "drones, be it guns or whatever else" - on aUScitizen.
The White House said Mr Tsarnaev would not be tried as an enemy combatant in a military tribunal because he was a naturalised UScitizen (born in southern Russia).
One must beacitizen or domiciliary (intent and presence plus facts and circumstances) to be subject to US transfer tax while simply spending one too many days in the US may subject you to US income tax.