I believe certain agencies in the US (FAA or NTSB etc...) help out other countries when planes crash. Smaller countries may not have the man power or skills necessary to handle a plane crash investigation. Especially if its an America plane, if they find a defect they will ground the fleet (787 Dreamliner for instance).

I have also heard sometimes countries call in the US or whatever EU agency to consult along with their personnel.

For satellites, wouldn't you want the most accurate data anyway? Using US, EU and Russian (even China/India) imagery would probably be better than pointing a finger at the right country/agency and saying we should use their images because the plane crashed in their country.