> He didn't smash the phone to pieces, he gave LE a hammer and they smashed the phone to pieces. It's entirely LE's own fault this happened -- they shouldn't have been trying to get into that phone, and it's their own fault it went wrong.

Setting a booby trap to destroy evidence that then gets destroyed when that trap is triggered is the same as destroying evidence. This is common sense, but also see https://en.wikipedia.org/wiki/Principal_(criminal_law)