Some interesting info on the speculation it was shot down:
A defence expert has told the BBC that shooting down a plane at 10,000m (9.7 miles) would have required a long- range surface-to-air missile - possibly guided by radar.
That suggests it is unlikely it could have been downed by a portable air defence missile, or Manpad, which has a much shorter range.
The only other possibility is for an aircraft at that height to be downed by a fighter carrying air-to-air missiles.
The US will have access to satellite imagery that should be able to identify ultra-violet plumes if a long-range surface-to-air missile was fired.
A defence expert has told the BBC that shooting down a plane at 10,000m (9.7 miles) would have required a long- range surface-to-air missile - possibly guided by radar.
That suggests it is unlikely it could have been downed by a portable air defence missile, or Manpad, which has a much shorter range.
The only other possibility is for an aircraft at that height to be downed by a fighter carrying air-to-air missiles.
The US will have access to satellite imagery that should be able to identify ultra-violet plumes if a long-range surface-to-air missile was fired.
Source: http://www.bbc.co.uk/news/world-europe-28354856
Edit:
Amateur video reportedly showing aftermath of the crash (from a distance):
http://www.theguardian.com/world/video/2014/jul/17/malaysia-...