Srimad Bhagavatam Canto 08, Chapter 24, Text 08

SB 8.24.8

kalenagata-nidrasya
 dhatuh sisayisor bali
mukhato nihsrtan vedan
 hayagrivo ’ntike ’harat
 
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
At the end of Brahma’s day, when Brahma felt sleepy and desired to lie down, the Vedas were emanating from his mouth, and the great demon named Hayagriva stole the Vedic knowledge.
Srimad Bhagavatam Canto 08, Chapter 24, Text 07
Srimad Bhagavatam Canto 08, Chapter 24, Text 09