I would vote against a single-blade-throwing scenario, as the aircraft is peculiarly intact in the photo. With the massive imbalance and rotation from one blade departing , i would expect to see a buckled or fractured tail boom, as well as the whole upper portion of the fuselage being ripped open from the transmission ripping itself out.. (think back to that squirrel crash in nz last xmas)
While i cant speak from experience myself i also would have thought mast bumping would come with tail and fuselage damage... as well as it being less likely from a more experienced pilot. Although only speculation; it might be a worthwhile guess that the aircraft had a previous mast bumping incident that went unreported, and may have damaged the mast internally.. for it to later fail in the cruise on this flight.. (in a positive G state.. pulling the rotor section away from the fuselage without impacting it)..
Very sad indeed.