Terrorists are not causeless wreakers of havoc, they have political goals.
From the newscientist.com
He's a poet of portentousness, a virtuoso of the causeless effect.
From the online.wsj.com
The movies always have a place for at least one causeless rebel whose choler is both enigmatic and unappeasable.
From the time.com
As the book closes, images play over and over in his head of the thoughtless, causeless, affectless brutality he has left behind.
From the guardian.co.uk
Thus, we have the appearance of a seemingly causeless selection event in a highly orderly and predictable formulation of the interference pattern.
From the en.wikipedia.org
More examples
Having no justifying cause or reason; "a senseless, causeless murder"; "a causeless war that never had an aim"; "an apparently arbitrary and reasonless change"
Having no cause or apparent cause; "a causeless miracle"; "fortuitous encounters--strange accidents of fortune"; "we cannot regard artistic invention as...uncaused and unrelated to the times"
Having no obvious cause; fortuitous or inexplicable; groundless or unreasonable