(CNN) -- Authorities found weapons, explosives and jihadist materials at an Islamic school in central Indonesia after a three-day standoff, police said Thursday.
Police descended on the Umar bin Khatab Islamic boarding School, in Bima, West Nusa Tenggara province, on Monday after an explosion there killed one person.
Students at the school, armed with machetes and arrows, blocked police officers who had gone there to investigate the explosion. The standoff ended Wednesday night when police opened fire and entered the school.
One person was injured by a stray bullet, according Maj. Gen. Anton Bachrul Alam with the National Police.
Seven people have been detained. The school's owner escaped, he said.
After searching the location, police found nine Molotov bombs, explosive materials, several jihadist videos, arrows and other homemade weapons, Alam said.
Two assembled bombs were also found under a bridge near the school but a police bomb squad was able to defuse them, he said.
The man who died in Monday's explosion was a member of the Jemaah Islamiyah terror network and trained as bombmaker in the Southern Philippines, according to local media reports. Police suspect he was showing students how to assemble a bomb that was going to be used in an attack on the police.
The school also is suspected of having ties with the organization Jamaat Tawhid Anshorut, or JAT, founded by jailed Islamic cleric Abu Bakar Bashir.
Last month, the radical cleric was convicted and sentenced to 15 years for helping set up a militant training camp in Aceh province. Bashir is also known as the former spiritual leader of Jemaah Islamiyah.
A JAT spokesman denied any connection between the school and the organization despite local media reports that quoted him saying otherwise.
"It doesn't have relation with JAT," spokesman Sonhadi, who goes by one name, told CNN. "It's not part of JAT." He later said that two former members of the organization worked at the school.