It is only when the elephant has been attacked or wounded, that he becomes a dangerous enemy.
With regard to the "rover" or "rogue," the case is quite different.

He is habitually vicious; and will assail either man or any other animal in sight, and without the slightest provocation.

He seems to take a pleasure in destruction, and woe to the creature who crosses his path and is not of lighter heels than himself! The rover leads a solitary life, rambling alone through, the forest, and never associating with others of his kind.

He appears to be a sort of outlaw from his tribe, banished for bad temper or some other fault, to become more fierce and wicked in his outlawry.
There were good reasons for fearing that the elephant they were spooring was a "rover." His being alone was of itself a suspicious circumstance, as elephants usually go, from two to twenty, or even fifty, in a herd.
The traces of ruin he had left behind him, his immense spoor, all seemed to mark him out as one of these fierce creatures.

That such existed in that district they already had evidence.