Eager to access valuable intelligence for its fight against militants, Egyptian military investigators were in Libya on Tuesday to join their counterparts interrogating the most wanted militant in Egypt, who was captured this week by a Cairo-allied Libyan force.
Hisham el-Ashmawi was captured in the eastern Libyan city of Derna, a longtime bastion of Islamic militants, by the self-styled Libyan National Army led by close Egyptian ally General Khalifa Haftar.
Egyptian security officials said el-Ashmawi's capture was the result of months of intelligence cooperation between the Egyptians and Libyans in the LNA. Teams of Egyptian investigators flew to Libya late on Monday and Tuesday to participate in the interrogation, said the officials, who spoke on condition of anonymity because they were not authorised to brief the media.
Egypt's close links with Hafter's army include the deployment in Libya of Egyptian military advisers and the sharing of intelligence. Egypt has in the past launched airstrikes against militants in Derna, on the Mediterranean.
Interrogating el-Ashmawi could potentially yield a wealth of information about militant groups fighting Egyptian security forces in the turbulent north of the Sinai Peninsula as well as in the country's vast Western Desert, scene of a number of deadly attacks blamed on militants infiltrating from Libya.
Authorities link the 40-year-old Egyptian to high-profile attacks in Egypt in recent years, including the 2013 assassination attempt against the interior minister at the time, Mohammed Ibrahim, as well as several others near the country's porous desert border with Libya, to which el-Ashmawi is believed to have fled last year.
While in Libya, el-Ashmawi, a former officer with the Egyptian army's special forces, set up the al-Mourabitoun, a militant group blamed by Cairo for most of the Western Desert attacks, including a 2017 ambush that killed nearly 30 Christian pilgrims on their way to a remote monastery.
Before he fled to Libya, he helped found Ansar Beit al-Maqdis, a jihadi organisation based in the turbulent north of the Sinai Peninsula. His military expertise - he left the military in 2011 - transformed the tiny group into a well-organised guerrilla band that later inflicted painful blows on Egyptian security forces in Sinai.
Beit al-Maqdis swore allegiance to the extremist Islamic State group in November 2014 and is now known as "Welayet Sinai," or the province of Sinai.
El-Ashmawi did not declare his allegiance to ISIS, which at that time was at the peak of its power, with its self-declared caliphate in control of about a third of both Iraq and neighbouring Syria.
In an audio recording released in 2015 that is believed to be authentic, el-Ashmawi allied himself with the Islamic State group's rival, al-Qaeda, led by Egyptian militant Ayman al-Zawahri.
Egyptian military officials at the time said el-Ashmawi was a suspect in the July 11, 2015 bombing outside the Italian Consulate in Cairo, which killed a bystander.
He is also named as a suspect in the 2015 killing of Egypt's chief prosecutor that year, the first successful assassination since the 1981 killing of President Anwar Sadat. Sadat's assassins were military officers who became militants.
El-Ashmawi was sentenced to death in absentia last year following his conviction on terror charges. The officials said he will most likely be extradited to Egypt where he would face a retrial.
Egypt, meanwhile, announced on Tuesday that its security forces killed 10 militants in a shootout in the city of el-Arish in northern Sinai. A statement by the Interior Ministry, which oversees security, said the shootout took place on a deserted farm used by the militants as a hideout.