Ramayana
हतश्चायं त्वया वृत्रो ब्रह्महत्या च वासवम् । बाधते सुरशार्दूल मोक्षं तस्या विनिर्दिश ॥ 7-85-19 ॥
"This Vritra has been slain by you, yet the sin of brahmin-slaughter afflicts Vasava (Indra); O tiger among the gods, ordain the release from it."
english translation