Police name mastermind of Kuta nightclub bombings as senior figure in terror group

Police in Bali have named the mastermind of last month's bomb attack as an Indonesian man believed to be a senior operative with a regional terrorist organisation.

Imam Samudra, alias Hudama, is thought to lead one of four South-east Asian chapters of Jamaah Islamiya (JI), an Islamist extremist group linked with the al-Qa'ida network. Intelligence officials believe he met JI's operations chief, Riduan Isammudin, in Thailand in January to plan the attack.

The chief investigator, General I Made Mangku Pastika, said Samudra – who reportedly always wears a hat and often carries a laptop computer case – decided where to plant the bombs in the Kuta Beach resort.

One of his associates, Umar Dulmatin, 32, a second-hand car dealer and electronics expert, triggered the explosions by mobile telephone. Dulmatin also helped to build the bombs, police believe. The explosions at the Sari Club and Paddy's Bar on 12 October killed nearly 200 people.

JI also organised an explosion near the American consulate in Bali minutes after the Kuta attacks, police said. No one was injured.

Samudra and Dulmatin were among six new suspects named by police, who released sketches and photographs. General Pastika said Samudra, 35 – who police believe also organised attacks on Indonesian churches in 2000 – learnt bomb-making techniques on visits to Afghanistan. After the blasts, he stayed in Bali for four days, watching the investigation.

The other suspects were named as: Ali Imron, 30, a teacher at the Al-Islam boarding school in Tenggulun and a courier for the group; Umar alias Wayan, 35, who allegedly placed the bomb in Paddy's; Idris, 35, who is believed to have bought the motorcycle found at the blast scene and handled accommodations and financing; and Umar, alias Patek, 35, who allegedly drove the motorcycle to Kuta.

Police said the group first met on 2 August in Solo. They then held three more meetings in the city, on the main island of Java, during August and September. The men went to Bali on 6 October, where they finalised the details.

"We are confident they are still in Indonesia," General Pastika said. "We want to arrest them as soon as possible. But it not easy to catch them because Indonesia is so big. It will depend on who is luckier, the police or the suspects."

Much of the information has come from a Javanese mechanic called Amrozi, who was arrested a fortnight ago. Amrozi met Samudra after travelling to Bali six days before the attack. Since his arrest on 5 November at home in Tenggulun, he has confessed to owning the explosive-laden minivan used in the attack outside the Sari Club and to having obtained the bomb-making materials.

Amrozi told investigators he met JI's operations chief, Riduan Isamuddin, also known as Hambali, in Malaysia, and studied under its spiritual leader, Abu Bakar Bashir. So far, police have not named Mr Bashir as a suspect. Mr Bashir has insisted he does not know Amrozi and that JI does not exist.