Germany has freed a Lebanese man who was sentenced to life in prison for hijacking an American airliner and killing a U.S. Navy diver 20 years ago.

German justice officials confirmed Tuesday that Mohammed Ali Hamadi was released on parole after a routine review of his case, and they say he already has left Germany.

Sources in Lebanon say Hamadi, a member of the Hezbollah militant group, has returned to Beirut, the focal point of the 1985 hijacking.

Hamadi was convicted in the hijacking of a TWA airliner that took off from Athens in 1985. U.S. Navy diver Robert Stethem, a passenger on the plane, was killed while the commandeered jet was on the ground in Beirut.

The German Foreign Ministry has denied any link between Hamadi's parole and the recent release of a German hostage in Iraq.

Some information for this report provided by AP and AFP.