Shiva Purana

siva.sh/siva-purana/saturda-samhita/9/59

शूलिनो ब्रह्मणो हत्या नापैति स्म च या क्वचित् ।। सा काश्यां क्षणतो नष्टा तस्मात्सेव्या हि काशिका ।। ५९ ।।

sanskrit

Brahmahatyā which did not leave Siva at any other place vanished in a moment at Kāśī. Hence Kāśī shall be resorted to for shedding off evil.

english translation

zUlino brahmaNo hatyA nApaiti sma ca yA kvacit || sA kAzyAM kSaNato naSTA tasmAtsevyA hi kAzikA || 59 ||

hk transliteration by Sanscript