Egyptian officials arrested Mohammed Al-Zawahiri, brother of top Al Qaeda chief Ayman Al-Zawahiri, according to The Huffington Post.
Authorities detained al-Zawahiri on Saturday at a checkpoint in Giza, a city across the Nile River from Cairo.
He was an alleged ally of ousted Egyptian President Mohammed Morsi, an Islamist, whose supporters are currently protesting against the killing of other supporters last week.
Officials stated earlier that al-Zawahri had commanded insurgents in Sinai Peninsula.
The source who provided information of al-Zawahiri's death has asked to remain anonymous and could not provide any more details as he was not authorized to speak with the press.
Street clashes on Friday reportedly left nearly 173 people dead, making the total death rate 750 since Wednesday. The clases continued on Saturday near a Cairo mosque where many Morsi supporters remained.
Morsi's Muslim Brotherhood leads an anti-military group that is committed to carrying out more protests to increase the turmoil going on in Egypt at the moment. The group said they will not stop trying until they take down the military-installed government.
His brother, Al Qaeda chief Ayman Al-Zawahiri, released a video last month pledging to set their terrorist allies in Guantanamo Bay free.
"We pledge God that we will spare no efforts to set them free along with all our prisoners, on top of them Omar Abdel Rahman, Aafia Siddiqui, Khalid Sheikh Mohammed and every oppressed Muslim everywhere," al-Zawahiri said.
The leader of Al Qaeda expressed another threatening message to the U.S.
"You are leaving a legacy of hatred and demands for vengeance from you over your crimes," he said in the video.