Kautilya's Arthashastra 13.2.22

13.2.22

tad eṣāṃ naimittikamauhūrtikavyañjanāḥ khyāpayeyuḥ //

Getting into an altar at night in the vicinity of the capital city of the enemy and blowing through tubes or hollow reeds the fire contained in a few pots, some fiery spies may shout aloud: "We are going to eat the flesh of the king or of his ministers; let the worship of the gods go on." Spies, under the guise of sooth-sayers and horologists may spread the news abroad.