Al-Mosmari was arrested a month after the attack. He was tried by a military court and sentenced to death in November last year.
The court also sentenced 15 other defendants for their involvement in the attack, including 10 in absentia, to life in prison. Another 17 got 5- to 15-year sentences.
Al-Mosmari was from Libya’s eastern city of Derna, which served as a safe haven for years for militant groups before the self-styled Libyan Arab Armed Forces took control of it early in 2018. The LAAF is led by military commander Khalifa Hifter, an ally to Egypt.
The defendants were accused of plotting and taking part in the 2017 attack on police forces as they raided the militants’ hideout. At the time, officials said the police force appeared to have fallen into a carefully planned ambush set up by the militants. The hours-long clash wounded another 13 security forces.
The security forces had been acting on intelligence and moving against a militant hideout backed by armored personnel carriers when they drew fire including and rocket-propelled grenades, officials said at the time.
They said the force likely ran out of ammunition and that the militants captured several police and later killed them. One officer who was taken was later rescued by the military.
Although the official death toll announced by the Interior Ministry was 16 police, with 15 militants killed or wounded, officials who spoke with The Associated Press at the time said more than 50 police were killed.
Days after the attack, President Abdel Fattah el-Sissi replaced his armed forces chief of staff. The Interior Ministry, which oversees police, dismissed the head of national security, a handful of generals and a dozen senior leaders responsible for the area where the deadly shootout occurred.
The attack took place in the al-Wahat al-Bahriya area, about 135 kilometers (84 miles) from Cairo. The area is the gateway into Egypt’s vast Western Desert which leads to strife-torn Libya.
For years, authorities have considered the area an infiltration path for smugglers and militants, and have blamed some past attacks on extremists transiting through.
Egypt has been for years battling Islamic militants located in the northern part of the Sinai Peninsula, but the insurgency gained strength after the 2013 overthrow of elected Islamist President Mohammed Morsi amid mass protests against his one-year, divisive rule.
Attacks have also spread outside Sinai and into the country’s mainland and areas close to the porous Libyan border to the west. The militants have mainly targeted security forces and Christians.
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