Srimad-Bhagavatam: Canto 4 - Chapter 1 - Verse 20


अत्रि: सन्दर्शयामास त्वरमाणं विहायसा ।कपालखट्‍वाङ्गधरं वीरो नैनमबाधत ॥ २० ॥


atriḥ sandarśayām āsatvaramāṇaṁ vihāyasākapāla-khaṭvāṅga-dharaṁvīro nainam abādhata


The great sage Atri again pointed out to the son of King Pṛthu that Indra was fleeing through the sky. The great hero, the son of Pṛthu, chased him again. But when he saw that Indra was carrying in his hand a staff with a skull at the top and was again wearing the dress of a sannyāsī, he still chose not to kill him.