Abu Dawud Book 33, Hadith Number 4451.

Narated By Sahl ibn Sa’d : A man came to the Prophet (PBUH) and made acknowledgment before him that he had committed fornication with a woman whom he named. The Apostle of Allah (PBUH) sent someone to the woman and he asked her about it. She denied that she had committed fornication. So he gave him the prescribed punishment of Lashes and left her.