Devi Asmarani, Jakarta – Indonesian police yesterday linked the blast at the Atrium Senen Plaza on Sunday to members of the Free Aceh Movement (GAM) rebel group who have been arrested for involvement in the Jakarta bourse blast last year.

Until two days before the bombing, the car used in the Sunday bombing belonged to Tengku Ismuhadi. He has been sentenced to 20 years in jail for the Jakarta Stock Exchange explosion which killed 10 people.

"After conducting an identification of the car's frame number, we found the car that was owned by Tengku Ismuhadi had been sold to someone else," Jakarta police spokesman Senior Commissioner Anton Bahrul Alam was quoted by the Detikcom online news service as saying.

He said Ismuhadi's wife had sold the car on the orders of her jailed husband. He added that 12 witnesses were being questioned about the blast, which damaged eight parked cars. No one was injured.

Sunday's blast was the third that rocked the Atrium Senen building, a shopping mall frequented by many of the lower middle-class Jakarta residents.

The first explosion took place last year, and the second on August 1. In all three blasts, police accused different groups as the masterminds.

Former president Suharto's son, Hutomo "Tommy" Mandala Putra who is on the run after being convicted of corruption, is also under suspicion of ordering some of the bombings. Police have said they found raw materials for making explosives at the house he allegedly lived in while in hiding.

The police also disclosed at a press briefing yesterday that a suspect in the Christmas Eve bombings of 18 churches last year was part of an international terrorist group with links to Afghanistan and Malaysia. The suspect, Dedi Setiono alias Abas who attended the press briefing, confessed to planting a bomb near the Roman Catholic Cathedral in the capital last Christmas Eve and has since been charged.

Abas told reporters he was trying to protect the interests of the Muslim community in Maluku province, where sectarian clashes with Christians have taken place over the last two years.

He said he belonged to a Malaysian militant Jihad group. In 1987, he trained in Afghanistan together with the Mujahideen fighters opposed to the Soviet occupation at the time. Police said the terrorist group is headed by two prime suspects currently at large, Hambali and Imam Samudra.

Said Police Deputy chief Brig-Gen Makbul Padmanagara: "This group has ties to international terrorist rings because 10 of their members, two of whom had been arrested, are Malaysian nationals. They have admitted to having trained in Afghanistan – and the Malaysians, who entered Indonesia through Sabah and Kalimantan – first went to Ambon to fight the holy war against the Christians there," he said. Abas and 13 other people, including a Malaysian national, were arrested in a West Java village two weeks ago.

Police had received a tip-off from another Malaysian who was arrested for alleged involvement in the bombing of the Atrium Senen Plaza on August 1. The group is also allegedly behind the bombings of two churches early this year.

Brig-Gen Makbul said the police were working with their Malaysian counterpart to track down other people linked to the terrorist ring.

The police have been under pressure to crack 38 bombing cases throughout the country since 1999. Brig-Gen Makbul said that only seven of these cases have not been solved.