Tharwat Salah Shehata was caught in an apartment in the 10th of Ramadan district of the city of Sharqiya on Monday, officials said.
They said he is held over accusations of forming militant groups in western Egypt and alleged involvement in a spat of killings of Coptic Christians in eastern city of Benghazi in Libya, and that he has been training militants in eastern Libya — a hub of extremist militia groups.
One of the groups, Ansar al-Shariah, has been blamed for the killing of the US Ambassador to Libya and three other Americans in Benghazi in 2012. Officials spoke on condition of anonymity because they were not authorized to speak to the press.
According to Libyan security experts Shehata has been in Libya's eastern cities of Darna and Benghazi — where there has been a sharp rise in targeted killings of security officers, activists and clerics.
Shehata, a member of the Egyptian Islamic Jihad group that assassinated former President Anwar Sadat in 1981, was sentenced to death for an assassination attempt on a former prime minister in the 1990s.
After the failed attempt, website The Long War Journal said that Shehata had "pursued jihad around the globe" traveling to Sudan, Afghanistan, Pakistan, Yemen and Iraq.
Then in 2001, his group merged with al-Qaeda under the banner of the so-called Global Islamic Front.
Since then, the United Nations has listed him as an al-Qaeda affiliate, saying he had worked together with Osama bin Laden. The UN said that Shehata was a member of the Egyptian Islamic Jihad's nine-member consultative council headed by al-Zawahri in charge of al-Qaeda organization work.
The arrest of Shehata comes as al-Zawahri's brother, Mohammed, has been jailed since the military ouster of Islamist President Mohammed Morsi in July. Under Morsi, he mediated between extremist groups and the presidency to cease attacks against military and police in the volatile Sinai Peninsula.
On Sunday, he was referred to trial by the country's top prosecutor along with 67 others on charges of forming and leading a terrorist group linked to al-Qaeda, and planning attacks.
BA/BA