In theory, telekinesis could be honed to the point where you could control molecules sufficiently to agitate them and cause heat or fire in an oxygen environment. Of course that would be a pretty advanced degree of control. Still it's theoretically possible given the nature of the power. But even at a less advanced level telekinesis has so many applications for destruction. Hell, if you could telekinetically pinch off someone's carotid artery and jugular vein, you could kill them pretty neatly. On an autopsy it would come up as an idiopathic (i.e. we don't know what caused it) cerebral hemorrhage, common enough. Unless of course it's not and there are telekinetic assassins out there. If there are I would like to become one.