Updated

An Arab TV channel aired footage Sunday taken minutes before last month's massive bomb blast killed former Prime Minister Rafik Hariri (search), showing a "suspect" white pickup truck that U.N. investigators have linked to the assassination.

The tape, taken Feb. 14 by a HSBC bank security camera, showed the open-backed 1995 or 1996 model Mitsubishi Canter (search) pickup truck entering the blast area shortly before Hariri's motorcade arrived near central Beirut's seafront St. Georges Hotel, the scene of the explosion.

The suspect truck, which was singled out in a report of a U.N. fact-finding mission investigating Hariri's assassination, was seen passing past the closed-circuit TV's lens six times slower than other vehicles before reaching the hotel.

Shortly after the truck passed out of the camera's view, Hariri's motorcade was taped entering the area.

Seconds later, the camera's view finder is obscured by clouds of dust and debris, the apparent result of the huge explosion that killed Hariri and 17 others. Lebanese opposition leaders have blamed Syria (search) and this country's Damascus-allied authorities for involvement in the killing. Both governments have denied such claims.

The tape was aired by Dubai-based Al-Arabiya TV.

The U.N. fact-finding mission's report into Hariri's killing poured scorn over the Lebanese murder investigation and said authorities had found out little about the truck, despite having access to the bank camera's tape.

"The [U.N.] mission ... accepts that the theory of this truck having been involved in the assassination is a credible theory, requiring full and extensive investigation," the report said.

It added that about one month after Hariri's killing, "little or no attempt had been made by the security forces to determine the movements of this suspect truck immediately prior to, or immediately after the explosion."

"This aspect of the investigation could have uncovered vital evidence," the report added, "including: the possible identity of the perpetrator or perpetrators, where the truck was parked immediately before the explosion and of critical importance, whether the truck continued on its journey and had no involvement in the assassination at all."

The U.N. team, which also inspected the tape, believed a Lebanese security force member planted "parts of a truck" in the bomb crater and local investigators later photographed the vehicle's remains there.

This created "serious suspicion and doubt about the actual involvement of this [Mitsubishi] truck in the assassination and seriously [damaged] the credibility of the main line of the investigation," the report added.

Justice Minister Adnan Addoum has denied evidence had been planted at the bomb scene, and has instead said wreckage of a car destroyed in the blast was retrieved by divers from the sea.

Late Sunday, Addoum threatened to prosecute opposition members attacking the government if Lebanese authorities are eventually cleared of involvement in the assassination.

"They must fully understand that making irresponsible allegations has its legal repercussions," he told the Lebanese Broadcasting Corporation. Addoum has been the target of an opposition campaign aimed at removing security chiefs for alleged negligence.

The bombing, caused by a TNT charge of about 2,200 pounds, enraged many Lebanese, sparked angry anti-Syrian protests and led to the brief ouster of this country's pro-Damascus government, plunging Lebanon into its worst political crisis since the end of the 1975-90 civil war.