The two Malaysians suspected of masterminding the latest suicide attacks in Bali are notorious for separate but complementary skills -- One is called a bomb-making expert and the other a smooth-talker adept at raising money and recruiting bombers.
Azahari bin Husin, known as the "Demolition Man" for his knowledge of explosives, and "Moneyman" Noordin Mohamed Top are believed to be key figures in the Jemaah Islamiyah terror group blamed for Saturday's bombings that killed 26 people.
The two became southeast Asia's most wanted fugitives after allegedly masterminding the 2002 nightclub Bali nightclub bombings that killed 202 people, and the Jakarta suicide attacks in 2003 and 2004, which left 23 more dead.
A top Indonesian anti-terror official, Maj Gen Ansyaad Mbai, also has identified the two as the alleged masterminds of the latest bombings.
Indonesian police say the two have eluded capture for years by renting cheap houses in densely populated areas, with nearby back alleys for quick escapes.
Azahari, an Australian-trained engineer, and Noordin were close associates of Jemaah Islamiyah's former operational chief, Riduan Isamuddin.
Isamuddin, an Indonesian better known as Hambali, was captured in Thailand in 2003 and is now in United States custody. The two Malaysians are believed to have taken his mantle even though this remains unconfirmed.
Azahari, a 48-year-old native of the southern Malaysian state of Johor, studied mechanical engineering at Adelaide University in Australia before getting a doctorate in property valuation from Reading University in the United Kingdom in 1990.
He taught at a Johor university before getting involved with Jemaah Islamiyah. Azahari is known to have received bomb-making training in Mindanao in the southern Philippines in 1999, and advanced training in Afghanistan in 2000.
He fled Malaysia, leaving behind his wife and two children, after police uncovered his Jemaah Islamiyah role during a crackdown after the September 11, 2001, attacks in the United States. Noordin, also from Johor, fled at the same time, and both arrived in Indonesia.
Dubbed the "Demolition Man" by Malaysian media, Azahari is believed to have become a militant firebrand after meeting Jemaah Islamiyah leader Abu Bakar Bashir in the 1980s.
Noordin, 35, is a recruiting whiz who purportedly excels at collecting money for the group's deadly missions. He was reportedly the chief strategist in the Marriott Hotel bombing in Jakarta in 2003, and the September 2004 attack on the Australian Embassy there.
Noordin is suspected of talking militants into becoming suicide bombers, using skills he picked up during stints in the southern Philippines, Indonesian police say.
In July 2004, Azahari and Noordin narrowly escaped a police raid on a rented house west of Jakarta, where forensic experts later found traces of explosives used in the Australian Embassy bombing.
Neighbours described both as reclusive men who left the property only to pray at a nearby mosque. The area's residents said before the embassy blast they saw the duo load heavy boxes into a white delivery van -- the same type used in that attack.
Militants arrested in connection with the Marriott bombing said Azahari attached ordinary soap bars to containers of flammable liquid next to the bomb. The mixture of sodium and fatty acid in the soap created deadly fireballs.