MH17: Launch site 'key' to identifying who fired missile

The Malaysian prime minister, Najib Razak, says an agreement has been reached with pro-Russian separatists in control of the area where a Malaysia Airlines plane crashed to give independent international investigators access to the site.

Rebel leader, Alexander Borodai, also agreed to hand over flight recorders to a Malaysian team in Donetsk.

However US satellite data may offer the best answers to what happened to flight MH17.

Richard Westcott reports.