Ali al-Bazzal was one of about 30 soldiers and policemen taken hostage by jihadist groups in August during clashes in Arsal, a town near the border with war-ravaged Syria.
"Muslim clerics handed over to the army the corpse of the martyr Ali al-Bazzal, who was kidnapped and executed by a terrorist group," the army said in a statement.
Bazzal was murdered execution-style by the Al-Qaeda affiliated Al-Nusra Front, which together with the Islamic State (IS) group kidnapped the Lebanese officers.
Lebanon's official National News Agency said Bazzal's family had arrived at the hospital to collect his body.
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A source in Arsal told AFP that a group of Muslim clerics had visited an Al-Nusra leader on the Syrian side of the border and received Bazzal's body from him.
Bazzal is one of four Lebanese state security forces who have been slain by jihadists on the outskirts of Arsal.
The town was rocked by heavy clashes in August 2014 between Lebanese security forces and Syrian armed groups, who kidnapped a number of Lebanese soldiers.
Al-Nusra announced on December 5 that it had killed Bazzal, publishing pictures of him being shot execution-style by a man standing behind him.
Behind the scenes negotiations for the release of the remaining hostages have repeatedly faltered.