Kautilya's Arthashastra 13.2.20

13.2.20

aśvapaṇyopayātā vaidehakavyañjanāḥ paṇyopāyananimittam āhūya rājānaṃ paṇyaparīkṣāyām āsaktam aśvavyatikīrṇaṃ vā hanyuḥ, aśvaiś ca prahareyuḥ //

Spies, under the, guise of merchants come to sell horses, may invite the king to examine and purchase any of the animals. While attentively examining the horses, he may be murdered in the tumult or trampled down by horses.