Al-Ḥākim's wickedness spread to the entire people, even to his sister. He accused his sister of prostitution and spoke very harsh words to her. His sister became angry with him and tried to kill him. She communicated with Ibn Dawwās, the greatest of the commanders. The two agreed to kill and eliminate al-Ḥākim. Ibn Dawwās assigned this task to two brave black slaves with him and said to them: "Be on the Mukattam mountain on such and such night, because on that night al-Ḥākim will come there to look at the stars. He will be accompanied only by his stirrup-bearer and a young slave. Kill al-Ḥākim as well as his stirrup-bearer and slave." This decision was made. On that night, al-Ḥākim said to his mother: "Tonight I have a great distress upon me. If I survive this, I will live about eighty years. But still, take my belongings with you; I fear most of all my sister. I am worried that she might do harm to you as well." His mother carried al-Ḥākim's belongings with her. In al-Ḥākim's chests were about three hundred thousand dinars and other jewels. His mother said to him: "O my lord, if the situation is as you say, then have mercy on me and do not go to that place tonight." His mother loved him very much. Al-Ḥākim replied: "No, I must go." As was his custom, al-Ḥākim used to walk around the palace every night. He walked that night as well. Then he returned to the palace. He slept until the last third of the night, then woke up and said: "If I do not go to that mountain tonight, I will burst." He immediately mounted his horse. His young slave and stirrup-bearer accompanied him. He climbed the Mukattam mountain. Ibn Dawwās's two slaves confronted him. They dismounted him from his mount, cut off his hands and feet, gutted him, and brought him to their master Ibn Dawwās.
Ibn Dawwās took the corpse and brought it to al-Ḥākim's sister. She buried him in her own house. The great commanders, the notables, and the vizier were summoned and the situation was explained to them. They pledged allegiance to al-Ḥākim's son Abū al-Ḥasan ʿAlī. They gave Abū al-Ḥasan ʿAlī the title Zāhir li-ʾIʿzāz al-Dīnillāh. However, Zāhir was in Damascus. His aunt called him and began to say to the people: "Al-Ḥākim told me: I will be absent from here for seven days, then I will return to you." The people calmed down. Then al-Ḥākim's sister ordered al-Ḥākim's two stirrup-bearers to go to the mountain, return, and tell the people: "We left al-Ḥākim at such and such a place," and then to go and tell his mother the same. They obeyed this order. Finally, the people were pacified. Al-Ḥākim's sister put forward Zāhir li-ʾIʿzāz al-Dīnillāh.
She sent him one million dinars and two million dirhams to come from Damascus. When Zāhir arrived, she dressed him with the crown of his grandfather Abū al-Muʿizz and a magnificent robe. She seated him on the throne. The emirs and chiefs pledged allegiance to him. He gave the emirs and chiefs many gifts and money. Al-Ḥākim's sister also dressed Ibn Dawwās in precious and magnificent garments. Then for three days she received condolences for the death of her brother al-Ḥākim. After that, she sent a group of soldiers to Ibn Dawwās to stand with their swords in his presence and serve him. Then one day she ordered them to say to him: "You are the killer of our lord," and to tear him apart with their swords. They carried out this order. Al-Ḥākim's sister killed everyone who knew the secret of al-Ḥākim's killing. Her prestige grew, and her respect increased.
Her influence in the state hierarchy increased. She found stability. Al-Ḥākim was thirty-seven years old on the day he was killed. He had spent twenty-five years of his life in rulership.