Skandapurana 5.222.11

5.222.11

atra yaḥ saṃkaraṃ kuryādyonestasya phalaṃ śṛṇu ..
brāhmaṇyāṃ brāhmaṇātputro brahmaghnaḥ saṃprajāyate .. 11 ..

Hear the fruit of him who causes confusion of birth here: / from a brahmin woman by a brahmin, a son who is a killer of brahmins is born;