Egyptian authorities have arrested the brother of al-Qaeda head Ayman al-Zawahiri, as part of their crackdown against supporters of ousted president Mohammed Morsi, officials confirmed on Saturday. Mohamed al-Zawahiri was detained  at a checkpoint in Giza, a town across the Nile from Cairo. Al-Zawahri is the leader of an ultraconservative Salafist group that operated openly in Egypt before July’s military coup. The group was allied with Morsi’s Muslim Brotherhood. In the past, Egyptian authorities said al-Zawahri was working closely with Islamist militants in Sinai Peninsula. Additional sources: AFP, AP