Looking at the maps that have been put up showing the crash site it strikes me that the aircraft's track to the VOR indicated on The map looks very very close to the ILS course.
Is it possible that they had mistakenly selected the VOR frequency rather than the ILS and flew what they thought was the localiser course straight towards the VOR with it's unexpected high ground in the way?
Pure speculation from a non-pilot so feel free to explain why this would or would not be possible.