'The bomb weighed over 10 kg'

Damar Harsanto and Fabiola Desy Unidjaja, The Jakarta Post Jakarta

Entering the sixth day of the investigation into the JW Marriott bombing, police estimated that the bomb contained between 10 kilograms and 20 kilograms of explosives.

"At least 10 kilograms of explosives would be needed for a device to cause such devastation," said a police detective close to the investigation.

The explosion, which claimed 11 lives and injured 148 others, produced a two-meter wide crater that penetrating through 32- centimeter thick concrete into the basement.

Another police detective close to the investigation gave a different estimate, however, saying that around 20 kilograms of explosives would be needed to cause such devastation.

Police found traces of the high explosives HMX, TNT and RDX, and low explosive powder at the blast site.

They said that the bomber had also placed four jerrycans containing gasoline around the bomb, which created a fireball effect after detonation. The fireballs instantly killed six of the victims.

As of Sunday morning, six officers from the National Police Central Forensics Laboratory and five officers from the Australian Federal Police were still busy searching the blast site for evidence and clues.

By applying special chemicals to items around the blast scene and then a special paper similar to Litmus paper, investigators are able to identify the presence or otherwise of explosives' residues.

"From the colors, we can identify traces of RDX, HMX, TNT, or the explosive powder used in the bomb. Then we can accurately estimate the quantity of explosives used in the bomb from where the traces were found," said a police detective at the scene.

Besides Australia, the United States has also offered assistance with the investigation.

Minister of Foreign Affairs Hassan Wirayuda told The Jakarta Post that U.S. Secretary of State Colin Powell phoned him on Saturday to offer help.

Powell also conveyed his sympathy to the Marriott bombing victims.

Hassan said that he had informed his U.S. counterpart on the latest developments in the investigation, saying that the bombing was related to the recent arrests of alleged Jamaah Islamiyah (JI) members in Semarang, Central Java.

Meanwhile at the bomb scene, the police had still not allowed the debris left by the bombing, including the wrecked Toyota Kijang van that contained the bomb, the shards of glass from blown-out windows, and bent and twisted metal window frames.

The two-meter-in-diameter crater have been covered with a large sheet of plywood.

Police have been linking the Marriott bombing to JI, saying that there were similarities in terms of the explosives used, the use of a mobile phone to trigger the bomb, and the removal of the engine and chassis identification numbers from the van containing the bomb.

Denpasar District Court has just handed down the death sentence to Amrozi for his involvement in last year's Bali bombings, which killed 202 people and wounded 300 others.

Police have announced that the suspected suicide bomber was Asmar Latin Sani, 28. It is he whom it is believed drove the van that exploded in the hotel's entrance driveway.

Two arrested JI members, Sardono Siliwangi and Muhammad Rais, told police that they had recruited Asmar as a JI member. Rais reportedly transported 50 kilograms of explosives from Palembang to Bengkulu in February this year. The explosives were kept at Asmar's house until 2003.

Separately, Jakarta Governor Sutiyoso said on Sunday that his administration would cooperate with the Jakarta Police to ensure better security in public places, including malls, hotels and entertainment centers.

"We'll check them at random in a month. If we find any of them failing to meet the security standards, we'll announce it openly to the public," he said.

Sutiyoso also said that his administration had officially requested the Jakarta Military Command to help ensure security in public places given staffing shortages in the police.

"The ratio of Jakarta Police officers to the city's population is about 1:925, much less than an ideal ratio set by the United Nations of 1:300. We need to narrow this wide gap by recruiting more personnel," he said, adding that members of the public should keep an eye on rented houses and low-cost hotels, which in most cases been used by the terrorists to plan and prepare their attacks.