BEIRUT -- From clues that include traces of explosives and a claim of responsibility by a bearded man, the mystery is deepening over who killed former Lebanese prime minister Rafik Hariri and how.
The Lebanese government and its Syrian supporters have been under intense domestic and international pressure to apprehend those responsible for the massive explosion that also killed 16 others and wounded more than 100 a week ago.
Foreign Minister Mahmoud Hammoud said yesterday that his government would "study" a request by the United Nations to involve a team of international investigators, adding it was "keen" to cooperate with the international body.
Lebanon has asked Switzerland to send DNA and explosives specialists but has rejected an internationally led inquiry, which was called for by Hariri's family, political opposition members, and France and the United States. The government has promised a thorough investigation and has condemned the attack.
An unsettled public has been pressing for answers sooner rather than later, and military specialists, politicians, and citizens have been weighing in with their own theories about the attack on Monday. Many Lebanese have little confidence in authorities who were unable to solve a string of assassinations during its 1975-1990 civil war.
"The bomb was placed underground, especially [since] the crater was so huge," said Hisham Jaber, a retired brigadier general and former professor at the Lebanese Military and Staff Command College. "Even a car with 1,000 kilograms [2,200 pounds] of TNT wouldn't create such a crater."
Jaber, who inspected the assassination site but is not part of the investigation, said a suicide attack was the least likely cause of the explosion. He noted the crater was near the middle of the road, indicating the bomb was probably placed under the street and not in a parked car.
Suspicion that the bomb was under the street increased Friday when the chief military investigator demanded that police investigate recent roadworks in the area.
Jaber said that although Hariri's motorcade had equipment to jam electronic transmissions, the device could have been circumvented by a wire-triggered bomb or a counterdevice placed in a nearby vehicle.
The Lebanese political opposition has accused the pro-Syrian Beirut government and its Syrian backers of being behind the attack. Both governments repeatedly have denied the allegations.
Hours after Hariri's assassination, Al-Jazeera satellite television aired a videotaped claim of responsibility by a bearded man. Lebanese security forces later announced that they raided the Beirut home of a Palestinian, Ahmed Abu Adas, who they said was the man in the video, but found no one.
Nobody answered at the door of Abu Adas's family residence yesterday. Several neighbors said Abu Adas was reclusive, did not have a job, and prayed five times a day at a nearby mosque. The neighbors said he sported a beard and wore a gown similar to that worn by Muslim fundamentalists and had not been seen for several weeks.
Officials have since downplayed the claim. Shortly after the attack, Justice Minister Adnan Addoum said the claim could be an attempt to mislead investigators, and the interior minister later suggested a suicide bomber backed by "international parties" may have been responsible.
Dia'a Rashwan, an Egyptian specialist on militant groups, ruled out the possibility that the videotape was made by militants since Abu Adas did not use Koranic verses commonly used by those who carry out attacks in Iraq and Israel.
"It is also very hard for a previously unknown group to start its work with such a huge attack," Rashwan said.
The Lebanese investigation has gone as far as Australia. Addoum asked Australian police to investigate 10 men who left Beirut the day of the bombing after he said traces of TNT were on two passenger seats. An Australian Federal Police spokesman said initial tests were negative. Australian police were waiting for a second round of test results yesterday.