Major pieces of the front of the plane appear to have been cut away, said Michael Bociurkiw, a spokesman for the Organization for Security and Cooperation in Europe, the group observing the crash site. Earlier, investigators observed someone using power tools to cut into the wreckage.

Rebels have said they had to move and alter big pieces to get at bodies and body parts. But the OSCE said what they saw was a “very invasive” altering of the wreckage.