Bhagavatapurana 6.18.58

6.18.58

evaṃ tasyā vratasthāyā vratacchidraṃ harirnṛpa /
prepsuḥ paryacaraj jihmo mṛgaheva mṛgākṛtiḥ //

58. Indra, who had his intention concealed, O king, was watchful to find some violation of the conditions on her part during the course of the observance and waited upon her like a hunter who puts on the guise of a deer (or the game).