Musannaf Ibn Abi Shaybah

Hazrat Nafi' reports that Hazrat Umar said: A slave girl of Hazrat Hafsa performed magic on her, and the people also felt the effects of the magic. That slave girl confessed to it. So, on the order of Hazrat Abdur Rahman bin Zaid, she was killed. When Hazrat Uthman heard of this, he disliked it and became very angry. Hazrat Ibn Umar (may Allah be pleased with them both) came to him and informed him that the slave girl had performed magic on Hazrat Hafsa, had confessed to it, and the people had also found the effects of her magic. Thus, it seems Hazrat Uthman disliked it because she was killed without his permission.