If terrorist group Jemaah Islamiah (JI) wanted to tell the world that it was still alive and active, no message could have been clearer than today's car bomb in Jakarta.

The bomb, which killed at least 10 and injured more than 100, ripped through the Marriott Hotel in Jakarta's new diplomatic district,
The timing left little doubt about the motives.

NO one really thought the monster was dead. It had taken many hits, its leaders locked away and its membership scattered, but Indonesia's gathering nightmare – Jemaah Islamiah – has outed itself as a beast far more resilient than even the best terrorist chasers had realised.

While JI has not put its hand up for the destruction at the Marriott hotel, there is little doubt in the minds of those who know it that Abu Bakar Bashir's band of militant Islamic radicals was responsible.

JI has never owned up to its previous attacks, being content to ride out the blame game while offering flat denials.

But the calling cards are unmistakably there. The lunchtime bomb, a massive high-explosive device concealed in an Indonesian-built Kijang, was designed for mass destruction. The target was an affluent, multinational hotel where dignitaries, wealthy Westerners and locals were sitting down to banquets. Next door, US and Australian diplomats and businessmen regularly gathered for meetings. But there were another two, more compelling reasons to focus suspicion. This week is rich in both symbolism and infamy for JI. Yesterday, former spiritual leader Bashir gave evidence at his own treason trial, in which he said killing could be justified under his interpretation of jihad. The bomb exploded less than two hours later.

Just as significant is the verdict expected tomorrow of the first person charged with the Bali bombings, Amrozi, an acolyte of Bashir and brother of two of the organisation's most important figures, Mukhlas and Ali Imron.

Amrozi is on the verge of a death sentence – so is a large swath of 38 of his cohorts rounded up after the Bali attack. They include three one- time heads of JI's four regions, Mukhlas, Mustafa and Mohammed Nazir bin Abbas – and the man who replaced Bashir after his arrest, Abdul Risduan. Also among them are senior bombmakers and henchmen.

But clearly, that has not diminished the group's capabilities. Despite the arrests, the heat from police and the heightened security around the capital, the bombers could still make this device and sneak it through to the heart of a prime target.

The take from this is that JI, the one-time sewing circle of like-minded Islamic radicals, is far more operationally ready, mobile and self-contained than regional police and spies had expected.

Like a multi-headed serpent, it is capable of maintaining momentum, focus and expertise despite its senior leadership being taken down.

There are still known to be nine senior figures on the run, among them Bali bombmakers Dr Azahari and Dulmatin and regional terror kingpin Hambali.

But of even more concern are the whereabouts of hundreds of others, who like, Ali Imron and many of the Bali bombers, also earned their terror stripes in Afghanistan.