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JI arrests, 20 years on: 4 members still detained under Internal Security Act, including Mas Selamat and son

SINGAPORE — Four members of the Jemaah Islamiyah (JI) terrorist organisation remain in detention under the Internal Security Act (ISA), out of 56 Singapore JI members detained without trial since 2002, the Internal Security Department (ISD) said on Saturday (Dec 4).

JI arrests, 20 years on: 4 members still detained under Internal Security Act, including Mas Selamat and son

A worn-out poster of Mas Selamat Kastari is pictured at a park in Singapore in 2008. He is one of four Jemaah Islamiyah members still detained under the Internal Security Act.

  • Out of the 56 JI members who had been issued detention orders since 2002, four are still being detained
  • Another six are still given restriction orders under the Internal Security Act
  • The four still being detained were not receptive to rehabilitation, said the ISD
  • While JI’s Singapore operations have been dismantled, the group remains a security threat


SINGAPORE — Four members of the Jemaah Islamiyah (JI) terrorist organisation remain in detention under the Internal Security Act (ISA), out of 56 Singapore JI members detained since 2002, the Internal Security Department (ISD) said on Saturday (Dec 4).

The four men remain "deeply entrenched in their radical beliefs and are assessed to pose an imminent security threat" despite the rehabilitation efforts, the department said in a report commemorating the 20th anniversary of its wide-ranging operations against JI.

The four are:

  • Mas Selamat Kastari, a JI leader who had planned to crash a hijacked plane in Singapore. He gained notoriety when he escaped from detention in 2008. He has been detained in Singapore since 2006
  • His son, Masyhadi Mas Selamat, who had received paramilitary training in Indonesia. He has been detained since 2013
  • Haji Ibrahim Haji Maidin, the first leader of the JI branch in Singapore. Ibrahim Maidin, a self-taught religious teacher who has undergone military training in Afghanistan, has been detained since 2002
  • Mohammad Aslam Yar Ali Khan, who was detained in 2001 in Afghanistan by the Northern Alliance, a group recruited by the United States to oppose the Taliban. ISD was tipped off that he claimed to know Al Qaeda’s Osama bin Laden and had fought in Afghanistan against Soviet forces. This intelligence led to the mass arrests against JI in 2001

Another six former JI detainees are still placed on restriction orders, ISD said.

A restriction order is issued when an ISA offence is not serious enough for a detention order. It requires the person to be placed under some restrictions such as being prevented from leaving the country.

Detention and restriction orders lapse after two years, but they can be renewed.

The remaining 46 detainees have been released and their restriction orders have lapsed. Another 13 JI members were the subject of restriction orders at the time, but were not detained. Their restriction orders have lapsed.

“The majority of them have reintegrated well into society and continue to (have) a close rapport with ISD case officers and rehabilitation stakeholders,” the department said on Saturday.

ISD said that its approach to rehabilitating offenders has been effective, as most of the detainees were receptive to those involved in the rehabilitation process and had put in effort in correcting their radical ideologies. Their families were also supportive.

“That said, rehabilitation only works for those who choose to be receptive,” it added, alluding to the non-co-operation of the four who are still being detained.

One of the four still believes in armed jihad, had expressed admiration for suicide bombers, and said that he would not hesistate to engage in suicide attacks if called on by the JI leaders to do so, ISD said without identifying which of the four detainees it was.

Another of the four, also not identified, has remained “openly hostile” to officers and to the rehabilitation programme.

“He regularly threatens to harm ISD officers and the Government. He also said that Singapore would burn in hellfire because of our secular society and that he would destroy Singapore.” 


Giving a prognosis for the threat posed by JI today, ISD said that the organisation's activities in Singapore have been dismantled and there is no current intelligence of any JI-linked terror plots targeting Singapore and its interests.

However, the regional JI network remains “quietly active” in Indonesia, where the group continues to conduct outreach and recruitment activities, it added.

A recent spate of operations by the Indonesian security authorities against the group since 2019 has diminished its operational capability temporarily, ISD noted.

The terrorist organisation is resilient and adaptable to a more hostile security environment and still represents a serious long-term security threat to Singapore since it continues to harbour the ambition to establish an Islamic state in Southeast Asia through violence.

The Taliban’s recent retaking of political control in Afghanistan may also allow Al Qaeda to re-establish safe havens there, ISD added. Both the Taliban and Al Qaeda had links to the JI.

“The Taliban’s victory after 20 years could also be viewed by JI as a validation of its long-game strategy, further entrenching the group’s aspirations to establish an Islamic state in the region,” ISD said.

CORRECTION: A previous version of this report stated that Masyhadi Mas Selamat had been detained since 2014 and Haji Ibrahim Haji Maidin since 2001. This was incorrect. Masyhadi Mas Selamat has been detained since 2013 and Haji Ibrahim Haji Maidin since 2002. We are sorry for the error. 

Related topics

Internal Security Act ISD Internal Security Department Jemaah Islamiyah JI terrorism violence

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