Indonesian police have arrested Abrori, the headmaster of a school where earlier this week a bomb exploded, sparking a two-day standoff between police and supporters of the school.
Police say the Umar bin Khatab school in West Nusa Tenggara Province, is linked to Abu Bakar Bashir, a radical Muslim cleric who has been convicted of supporting terrorists in the country.
On Monday, a bomb exploded at the school, killing a man. When police arrived to investigate, teachers and students armed with machetes and other weapons, blocked their way. Police were able to enter on Wednesday, and say they found a cache bomb-making material, guns and literature advocating violence.
Indonesia, which has the world's largest Muslim population, has suffered sporadic terrorist attacks by militant Islamists. The worst was the 2002 bombing in a tourist area on the island of Bali which killed more than 200 people.
The Indonesian government, which is secular, has cracked down on militants and has arrested, charged and convicted scores of people tied to terrorist attacks.