Lebanese security forces arrested a former mayor of the town of Arsal near the Syrian border on Saturday in connection with the capture of Lebanese soldiers, security sources said.
Ali al-Hujeiri also stands accused of collusion with the Nusra Front Islamist group, al Qaeda’s former Syria branch, the sources said.
Militants from the Nusra Front and Islamic State (IS) militant group briefly overran Arsal in 2014 and captured a number of soldiers before they withdrew during clashes with the army.
Nusra Front released 16 soldiers in 2015 in exchange for the release of jailed Islamists.
IS killed all nine soldiers it had captured.
Both groups were driven from their last foothold at the Syria-Lebanon border in recent separate offensives by the army and Lebanese Shi‘ite group Hezbollah.
It was not immediately clear which group of captured soldiers Hujeiri was being accused over.
Lebanese President Michel Aoun said this week the army was investigating the circumstances that led to the capture of the soldiers killed by IS.