Justification could be (for the sake of argument): serious threat to national security / several lives at stake / not feasible to apprehend physically (jurisdiction, unfriendly government etc etc.)
If upon scrutiny the reasoning behind his demise were not justified:
proper adjustments must be made and compensation and punishment doled out.
else
continue
addendum: People seemed ok with this when it was Osama, but not this guy. Seems like the method was less of an issue and it mattered much more about who it was. I agree with that sentiment.