It was "a mistake".
The findings of United States intelligence officials who have been setting out a more formal assessment of the evidence they hold into the shooting down of the Malaysian airliner.
The Office of the Director of National Intelligence admitted that the US does not know who fired the surface-to-air missile.
And also that they have no evidence of direct Russian involvement.
"We don't know who pulled the trigger" they said, adding that it was "probably" the pro-Russian separatists who fired it.
Given the pressure that has been building for new sanctions against Russia - the lack of any direct intelligence implicating President Putin is significant - particularly on the day European leaders were debating that subject.
According to the briefing - the US did not know that the separatists had a SA-11 surface-to-air missile launcher until after the passenger jet was shot down.
The officials did not provide satellite imagery of the missile launch despite some suggestions that the US does have that material.
All that they could conclude was that the missile was launched from regions controlled by the separatists.
The most plausible explanation, one official said, is this was "a mistake" by inexperienced people.