For all we know he could have been a terrorist planning an attack on Israel, they found out about it and had him taken out, authorities may have realised this and decided to err on the side of caution re: the house.
One of a million possible scenarios.
Perhaps the house could have been rigged up to explode upon their return if the alps job had failed.
Why Israeli?
Also why did the house not go up when other people went in it!?

