Uttara-kāṇḍa - Part 5 - Rāma recognises Kuśa and Lava as the sons of Sītā
Lakṣmaṇa described to Rāma the glory of the aśvamedha and narrated the story of Indra vanquishing Vṛtrāsura. Upon performing the aśvamedha to Bhagavān Viṣṇu, Indra got rid of his fear of brahmahatyā doṣa, which he had acquired upon killing the rākṣasa. Brahmahatyā then took residence in four different places – first, as froth in rivers; second, as latex in trees; third, as menstrual blood in youthful women; and fourth, in those who kill the brāhmaṇas.
