Kautilya's Arthashastra 12.5.7

12.5.7

gandhapraticchannaṃ vāsya tīkṣṇaṃ dhūmam atinayet //

A wall or a stone, kept by mechanical contrivance, may, by loosening the fastenings, be let to fall on the head of the enemy when he has entered into a temple; stones and weapons may be showered over his head from the topmost storey; or a door-panel may be let to fall; or a huge rod kept over a wall or partly attached to a wall may be made to fall over him; or weapons kept inside the body of an idol may be thrown over his head; or the floor of those places where he usually stands, sits, or walks may be be sprinkled with poison mixed with cow-dung or with pure water; or under the plea of giving him flowers, scented powders, or of causing scented smoke, he may be poisoned; or by removing the fastenings made under a cot or a seat, he may be made to fall into a pit containing pointed spears; or when he is eager to escape from impending imprisonment in his own country, he may be led away to fall into the hands of a wild tribe or an enemy waiting for him not far from his country; or when he is eager to get out of his castle he may be like- wise misled or made to enter an enemy's country which is to be restored (to the conqueror); the enemy's people should also be kept under the protection of sons and brothers (of the conqueror) in some forts on a mountain, or in a forest, or in the midst of a river separated from the enemy's country by wild tracts of lands.