Lebanon arrests former Arsal mayor suspected of Nusra collusion
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 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.
Islamic State 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 Shia group Hizbollah.
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 the Islamic State group.