Hadith.5035 - It is narrated from Ammar ibn Musa Al-Sabati that Abu Abdullah (as) said
I asked Imam (as) about a man against whom three men testified that he had committed adultery with a certain woman, but the fourth witness testified that he did not know with whom the man had committed adultery.
Imam (as) replied: "He is neither to be punished with lashes nor stoned."
Imam (as) was also asked about a married woman who committed adultery and was pregnant. Imam (as) said: "She should be kept until she gives birth to what is in her womb and nurses her child, then she is to be stoned."