Ayman has said that he has a deep affection for his mother. Her brother, Mahfouz Azzam, became a role model for Ayman as a teenager. Ayman has a younger brother, Muhammad al-Zawahiri, and a twin sister, Heba Mohamed al-Zawahiri. Al-Zawahiri's sister, Heba Mohamed al-Zawahiri, became a professor of medical oncology at the National Cancer Institute, Cairo University. She described her brother as "silent and shy". Muhammad worked in Bosnia, Croatia, and Albania under the cover of being an International Islamic Relief Organization (IIRO) official. While hiding in the United Arab Emirates, he was arrested in 2000, then extradited to Egypt, where he was sentenced to death. He was held in Tora Prison in Cairo as a political detainee. Security officials said he was the head of the Special Action Committee of Islamic Jihad, which organized terrorist operations. However, after the Egyptian popular uprising in the spring of 2011, on March 17, 2011, he was released from prison by the Supreme Council of the Armed Forces, the interim government of Egypt. His lawyer said he had been held to extract information about his brother Ayman. However, on March 20, 2011, he was re-arrested. On August 17, 2013, Egyptian authorities arrested Muhammad al-Zawahiri at his home in Giza.