NO, terrorits are responsible for planting a bomb and calling (meaning, so, no lifes taken).

Police is responsible for knowing a place is about to be bombed and not evacuate for whatever reason.

If you go to a place where they are bombing a building for constrution purposes, for example, and the workers don't warn you that you can not enter, and you die inside?

Whose is the fault? The one who put the dynamite or the ones who knew it was going to explode and didn't warn you as it was their duty?

How would you have felt if the police had known with half an hour in advance the twin towers crash, and they hadn't evacuated the people being able to do so?

If I were their family I would have sued them to the last.