The man named as the main suspect last night is a Malaysian who was educated in Britain, a gifted mathematician who completed a doctorate at Reading University in 1990.
In Malaysia the newspapers call him the "Demolition Man". Azahiri Husin is said to be the chief bomb-maker for Jemaah Islamiah, the south-east Asian militant group believed to be a major ally of al-Qa'ida, which Indonesian police believe was behind yesterday's bombing.
A former university lecturer, Mr Husin is believed to have written a manual on bombmaking that was used in the 2002 attack on a Bali night club in which at least 202 people died. He is also suspected of being behind a bomb attack on the Marriott hotel in Jakarta in August last year, in which 12 died.
In his youth he is said to have shown little sign of the Islamic militant he was to become. In the Seventies, he studied in Australia; in the Eighties, he studied at Reading. He returned to Malaysia, then he moved to Indonesia, where he and his wife both became university lecturers.
In the Nineties, he fell under the influence of Abu Bakar Bashir, the alleged spiritual leader of Jemaah Islamiah, who is being held in Indonesia, and another preacher who was advocating jihad, Abdullah Sungkar. Police believe his wife's illness may have pushed him into the arms of Islamic militancy. He went to Afghanistan, where he attended an al-Qa'ida training camp, then had further training in the Philippines.
Long before 11 September 2001, Osama bin Laden is believed to have worked hard to form alliances in the region. Operation Bokinka, a plot to bomb 11 US civilian aircraft simultaneously, amid other attacks, is believed to have been planned from south-east Asia.
The militants had more than one reason to target Australia. Not only is the country one of America's few remaining allies in Iraq, Australia has also been a major ally for the Indonesian government in its attempts to crack down on Jemaah Islamiah. If the group was behind yesterday's bombing, its leaders had a personal grudge to settle.
Indonesia has arrested, tried and convicted scores for past bombings, but yesterday proved that the militants are still able to strike. The country's intelligence chief, Hendropriyono, said Indonesia's anti-terrorism laws were too weak. If the Australian embassy was the symbolic target, the bombers succeeded in killing mostly Indonesians on Rasuna Said Street outside.
The bombers could not get inside the embassy, and they detonated their explosives in the street. "Before the bomb blast, a mini-van car intentionally hit the road divider which was placed in front of the embassy's gate," said Ismanto, an embassy security guard. Then all hell broke loose."
Suwardi, 39, said he was at a building just behind the embassy applying for a job. "I tried to run away after the bang," said Suwardi. "But the impact of the bomb was just so big. The perpetrators are not human. They're animals, they're devils. They must be fought."