[asteli]

That's not limited to any one bombing -- it was pretty typical of them to time their bombs would go off at night, as well as phone them in. They would also locate the bombs in places where they were relatively unlikely to hurt people: in the floor drain of a restroom, in a disused room, up in the ceiling.

There's a fascinating history of the militant revolutionary movements that cropped up around 60s, Days of Rage by Bryan Burrough.