Ice cream seller Mahmoud Bazzi, 71, was returned to his homeland where he could ultimately stand trial for the abduction, torture and killing of the peacekeepers while serving with a Christian militia.
Privates Derek Smallhorne, 31 at the time and from Dublin, and Thomas Barrett, 30 and from Cork, were on duty with the UN Interim Force in Lebanon (Unifil) near the Israeli border on April 18, 1980 when they were captured.
Both were married with three children.
They had been in a three-vehicle convoy that was stopped by the South Lebanese Army (SLA) which was controlling the war-torn region at the time and in conflict with the Palestinian Liberation Organisation (PLO).
Tensions were high in the area on the day of the attack as the peacekeepers moved supplies to a border post.
Twelve days earlier clashes between the SLA and Dutch and Irish soldiers serving with the UN left an Irish man and a militia man dead. The SLA had vowed to avenge the killing.
US Immigration officials confirmed Bazzi was deported from Detroit to Beirut yesterday and handed over to Lebanese authorities after he admitted in court lying to obtain immigration status in America in 1994.
Rebecca Adducci, field office director for the US Enforcement and Removal Operations in Detroit said: “This should provide a stark warning to those who seek to game the system to obtain immigration benefits.”
Bazzi had originally been traced to the Detroit area by an RTÉ Prime Time investigation in 2000.