The United States Central Intelligence Agency once referred to Hambali as South-east Asia's Osama bin Laden.
Proof of his importance to the Jemaah Islamiah (JI) leadership was evident when the regional terror network began to decline after he was nabbed in Bangkok in 2003.
His capture came after he successfully orchestrated the 2002 Bali bombings that killed 202 people. The blasts on the night of Oct 12, which targeted nightclubs in the tourist district of Kuta and the United States consulate in Denpasar, remain the deadliest terror attack in modern-day Indonesia.
Hambali, whose real name is Riduan Isamuddin, was transferred to Guantanamo Bay detention centre in 2006 and was said to be awaiting trial at an American military tribunal.
Now aged 50, he is still wanted by Malaysia, Singapore and the Philippines for terrorism activities. Among the terror activities he is linked to is a meeting which he had arranged between two of the Sept 11, 2001 hijackers and Al-Qaeda figures in Malaysia in 2000.
In December 2001, months before the Bali bombings, 15 JI operatives were arrested in Singapore for planning attacks on government buildings, embassies and US servicemen in the Republic.
Hambali later called for a meeting of other JI operatives in Bangkok and ordered attacks on soft targets frequented by Westerners.
That was when the plan to attack Bali in 2002 was hatched.