Among members of the Jamaah Islamiyah, Ali Fauzi Mazin was known as an expert bomb-maker, and an able mentor in bomb-construction. Together with Ali Imron, he made the bombs that were detonated at Paddy's Pub, Sari Club, and the US Consulate in Denpasar, Bali, in 2002.

A number of his students became the perpetrators of the bombing of the JW Marriot Hotel in Mega Kuningan, Jakarta, which killed 14 people and injured 156 others in June 2003. A yea