Islamic militant group Hezbollah has denied that one of its members was the suicide bomber who attacked a Jewish community centre in Argentina in 1994.
The blast was the worst terror attack in Argentina's history
An Argentine prosecutor said Ibrahim Hussein Berro of Lebanon had been identified in a joint effort by Argentine intelligence and the FBI.
But Hezbollah said that he had died in southern Lebanon while fighting Israel.
Argentina's Jewish community has for years sought a resolution to the attack in Buenos Aires that killed 85 people.
Islamic militants, backed by Iran, have long been suspected of carrying out the blast that wounded more than 200.
Prosecutor Alberto Nisman said friends and relatives had identified a photograph of Hussein Berro.
His two US-based brothers had testified that he had joined the radical Shia militant group, Mr Nisman said.
But Hezbollah described the accusations as "categorically false".
"The martyr Ibrahim Hussein Berro was among the mujahedeen [fighters] brothers who were martyred [killed] during a confrontation between the Islamic Resistance [Hezbollah] and the Israeli occupation forces in southern Lebanon," it said in a statement.
Sceptical of claims
The car bomb at the Jewish Argentine Mutual Association (AMIA) was one of two attacks targeting Argentina's 200,000-strong Jewish community in the 1990s.
Argentine, US and Israeli officials have all said that Iran is to blame - a charge Tehran denies.
Independent investigators are sceptical, correspondents say.
They point to repeated incompetence and deception in the official investigation, in which no proper autopsies or DNA tests were done on human remains at the site.
Members of Argentina's Jewish community have repeatedly accused the government of the former president, Carlos Menem, of obstructing the inquiry, which it denies.
In July 2005, President Nestor Kirchner's government issued a decree formally accepting a share of the blame for the failure of investigations into the AMIA attack.