Yahya related to me that Ziyad ibn Abd ar-Rahman said, "Malikrelated to us from Sumayy, the mawla of Abu Bakr ibn Abd ar-Rahman,that Abu Bakr ibn Abd ar-Rahman was once doing itikaf and he would goout to relieve himself in a closed room under a roofed passage inKhalid ibn Walid's house. Otherwise he did not leave his place ofitikaf until he went to pray at the Id with the muslims."
USC-MSA web (English) reference: Book 19, Hadith 5
Arabic reference: Book 19, Hadith 697