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