Born in Kluang, Johor, Malaysia, he is thought to have been a key bomb maker and/or financier for Jemaah Islamiyah (JI) and to have left JI and set up a more violent splinter group Tanzim Qaedat al-Jihad.[3] Noordin was reported by the FBI to be "an explosives expert". The FBI reported him as "an officer, recruiter, bomb maker and trainer for the Jemaah Islamiah (JI) group."[4]