TERRORIST Mas Selamat Kastari, who walks with a limp, broke his left leg while trying to escape from a Bintan jail after he was arrested in Feb 2003, said terrorism expert Rohan Gunaratna.

He was sentenced to 18 months jail in Bintan for immigration offences. While serving his jail term, he attempted an escape by jumping from a high floor in the prison.

He did not get away because he broke his leg, said Dr Gunaratna, a security analyst at the International Centre for Political Violence and Terrorism Research, who has described the leader of the Jemaah Islamiah (JI) militant network here as 'the most ruthless of the JI Singapore members'.

When detained by the Indonesian police for the first time, Mas Selamat had been on the run in Denpasar, Surabaya, Medan and Padang, before reportedly working as a farmer on Kundur island - about an hour's ferry ride from Singapore. Among other things, he had on him a book on the virtue of suicide.

He told the police that he supported himself from his savings, but that relatives from Singapore who visited him also provided him and his family with funds.

His escape from the Whitley Road Detention Centre on Wednesday was the third escape from legal custody and government dragnet.

He fled a government dragnet in Dec 2001 following the arrests of Singapore JI members in an Internal Security Department operation in which the authorities discovered the militant leader's plans to crash seven trucks filled with bombs at various locations around the island.

Some 13 JI members planning attacks against a number of foreign and local targets here, including the Causeway, were nabbed in that operation.

The 1.6m-tall Indonesia-born former resident of Teck Whye Lane, thought to have worked as a mechanic here, escaped. He then hatched an even deadlier plot to hit back at Singapore for arresting his JI colleagues.

Said to have been inspired by the Sept 11, 2001 attacks on America by Al-Qaeda, Mas Selamat and several other JI members planned to hijack an aircraft flying out of Bangkok and crash it into Changi Airport in early 2002.

To circumvent stringent airport checks, they did not plan to carry weapons on board, but intended to have the two physically stronger members in their group force their way into the cockpit.

But the plot was foiled when Mas Selamat's name appeared in the media, proclaiming him as being wanted in connection with JI activities.

He was arrested again in Malang, Indonesia, in 2006, for carrying false identification papers. He was handed over to Singapore authorities in Feb 2006 and detained under the Internal Security Act in March that year.

On Wednesday, he managed to slip away from the Whitley Road Detention Centre while he was being taken to meet his family at the visitors room. On the way to the family visit room, he asked to go to the toilet where he escaped.

Mas Selamat's involvement in JI began in 1990, when he joined Darul Islam, a movement considered to be the parent organisation of the JI and that fought for an Islamic state in Indonesia in the 1950s.

According to a report by the International Crisis Group (ICG), he joined the group after he had heard Indonesian cleric Abu Jibril preach in Johor.

By 1992, he had joined the religious council of the Singapore JI cell. A year later, he travelled to Afghanistan for military training supervised by another Indonesian cleric.

In 1998, JI paid for Mas Selamat and another JI member to visit Afghanistan for a month to look at the Taleban system of government. The ICG report noted that they returned home 'deeply impressed'.

In 1999, Mas Selamat was chosen by JI operations chief Hambali - now in US custody in Guantanamo Bay - to take over as JI leader here from Ibrahim Maidin, who was nabbed in 2001 and remains in detention.

Mas Selamat's role included directing Singapore JI members to undertake reconnaissance of various establishments and handing over the material so gained to JI operational leaders based in Malaysia.

The hit list included the United States Embassy and American Club, the Defence Ministry headquarters at Bukit Gombak and the Education Ministry building at North Buona Vista Drive.

Mas Selamat, who used to sport a moustache and goatee, has five children believed to be aged between seven and 19 now.