Kautilya's Arthashastra 13.2.12

13.2.12

taṃ rājā yam arthaṃ yāceta tam asya kariṣyamāṇaḥ "saptarātram" iti samānam //

When an ascetic, pretending to be able to find out hidden treasure trove, is seated with his body burning with magical fire at night in a lonely place, his disciples may bring the king to see him and inform the king that the ascetic can find out treasure trove. While engaged in performing some work at the request of the king, the latter may be requested to come and remain at the spot for seven nights... (as before).