By Irwin Arieff UNITED NATIONS, Dec 12 (Reuters) - Working from a tooth and 33 tiny bits of burned flesh, U.N. investigators sketched out on Tuesday a rough portrait of the suicide bomber they believe assassinated former Lebanese Prime Minister Rafik al-Hariri. While the experts looking into Hariri's murder have not suggested who may have ordered the killing or set it up, it described the presumed bomber as a man in his early 20s who had spent two to three months in Lebanon prior to his death in the Feb. 14, 2005, blast. Working with evidence gathered at the murder site in a Beirut street, the investigators said they believed he was standing next to, or was inside of, a Mitsubishi van containing a charge equivalent to around 4,000 pounds (1,800 kg) of TNT. The charge consisted either of a mix of RDX and TNT, with a detonating cord of PETN, or of TNT and Semtex, chief investigator Serge Brammertz said in a report to the U.N. Security Council. Investigators said they believed the truck bomb was set off at the site rather than from a remote location partly due to the presence on a few bits of the bomber's body of a plastic material that "possibly comes from electric wires" that would be associated with a triggering device. The crown of an upper right central incisor tooth thought to have been in the bomber's mouth showed "a distinguishing mark ... rarely seen among people from Lebanon," the report said, leading investigators to include he was born elsewhere. Furthermore, an analysis of "the ratio between isotopes in elements found in different parts of the person's body" showed that the man spent neither his youth nor the last 10 years or so of his life in Lebanon, the investigators said. But he was in Lebanon "in the last two to three months before his death," they said. The report said the ratio between isotopes found in different parts of the body vary depending, among other things, on where an individual was living when a particular body part was formed. For example, dense bones and tooth enamel are formed in childhood, while the portion of a hair closest to the skin is formed as recently as two weeks before a person's death. While investigators also have data from that analysis on "the type of area in which the individual lived" during the last 10 years or so of his life, they have not yet been able to match the data with a specific place and were still looking for the right spot, their report said.
