وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ نَافِعٍ، عَنْ رَجُلٍ، مِنَ الأَنْصَارِ أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم نَهَى أَنْ تُسْتَقْبَلَ الْقِبْلَةُ لِغَائِطٍ أَوْ بَوْلٍ ‏.‏

Yahya related to me from Malik from one of the Ansar that theMessenger of Allah, may Allah bless him and grant him peace, forbadedefecating or urinating while facing the qibla. Translation Not Available

Book Ref: Muwatta Imam Malik Book 14 Hadith 459
Web Ref:  Muwatta Imam Malik Book 14 Hadith 2