SB 6.13.2
devarsi-pitr-bhutani
daitya devanugah svayam
pratijagmuh sva-dhisnyani
brahmesendradayas tatah
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
Thereafter, the demigods, the great saintly persons, the inhabitants of Pitrloka and Bhutaloka, the demons, the followers of the demigods, and also Lord Brahma, Lord Siva and the demigods subordinate to Indra all returned to their respective homes. While departing, however, no one spoke to Indra.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
In this connection Srila Visvanatha Cakravarti Thakura comments:
brahmesendradaya iti; indrasya sva-dhisnya-gamanam nopapadyate vrtra-vadha-ksana eva brahma-hatyopadrava-prapteh; tasmat tata ity anena manasa-sarovarad agatya pravartitad asvamedhat parata iti vyakhyeyam.
Lord Brahma, Lord Siva and the other demigods returned to their respective abodes, but Indra did not, for he was disturbed at having killed Vrtrasura, who was actually a brahmana. After killing Vrtrasura, Indra went to the Manasa-sarovara Lake to become free from sinful reactions. When he left the lake, he performed an asvamedha-yajña and then returned to his own abode.