Nissim Nasser is an Israeli citizen convicted of spying for Hezbollah, who has been deported to Lebanon.
Rumours say the release could be part of a prisoner swap, as Lebanese group Hezbollah returned remains of Israeli soldiers, killed in the 2006 war.
Nissim Nasser was born in 1968, in Lebanon to a Jewish mother and a Shia Muslim father. In 1982, he left the country during the Israeli invasion, joined his family in Israel, became an Israeli citizen and settled near Tel Aviv.
But his citizenship was revoked by Israel a month ago, at the end of his six-year sentence. In an unmarked white jeep, Mr Nasser was driven to the border crossing near Lebanon’s southern town of Naqoura, and handed over to the International Committee of the Red Cross (ICRC).
A celebratory party had been prepared by Hezbollah officials, for his return. A stage was erected near the border, with loudspeakers blaring patriotic music across a main square.
In 2006, Hezbollah captured two Israeli soldiers, which prompted the 33-day war between Israel and the Shia militant group, who could be part of a more extensive prisoner swap between the two sides. It could also involve a number of Lebanese citizens by Israel.
Hezbollah has not commented those rumours, and Israel has denied this deportation being part of any wider deal.
But as Nissim Nasser was released, Hezbollah said it had handed over the remains of two Israeli soldiers that were killed during the 2006 war to the ICRC, so they could be returned to Israel.
The ICRC confirmed turning a box over to Israel, that contained human remains and was coming from Hezbollah.
To BBC’s Mike Sergeant in Beirut, the exchange clearly shows that negotiations had been going on behing the scenes, maybe facilitated by German mediators.