A tooth found at the scene of the murder of ex-Lebanese PM Rafik Hariri could help to identify the probable suicide bomber, UN investigators say.
Mr Hariri was killed in a massive blast in February 2005
In their latest report, they say they believe a man who died in the February 2005 blast is likely to have detonated a truck bomb which killed Mr Hariri.
The chief investigator asked several states to help to identify the bomber by his teeth and other pieces of DNA.
They are "the business card of a person," Serge Brammertz said.
"This can be an extremely important lead to identify those persons who have put this person in a position to act."
The report says new leads about who was behind the attack in Beirut have been uncovered, but it does not elaborate.
Syria has denied involvement in the blast, in which 23 people died.
The report was delivered to UN Secretary General Kofi Annan on Monday and the Security Council met on Friday to discuss Mr Brammertz's latest findings.
They reinforce earlier suggestions that Mr Hariri was assassinated by a large truck bomb.
Investigators believe the man detonated about 1,800kg (3,960lb) of explosives from either inside or directly in front of the truck.
The document says a tooth found at the scene and believed to belong to the bomber had a distinctive crown, suggesting the attacker came from abroad, according to the Associated Press news agency.
It says investigators found 32 pieces of what are believed to be the bomber's remains, putting him between 20 and 25 years old.
"Further forensic tests are taking place to possibly establish the regional origin of the person," Mr Brammertz said on Friday.
"His DNA is being compared with existing DNA databases in several countries." He declined to name the countries.
Mr Hariri's death triggered huge demonstrations in Lebanon against the Syrians.
Damascus denied involvement but eventually bowed to international pressure, pulling out its troops after nearly 30 years of military presence.