By Jonathan Head BBC South East Asia correspondent

It is now one month since the devastating bomb attack in Bali and the Indonesian police are reporting significant progress in their investigation.

After a series of false leads, mistaken identities and muddled statements, they appear to have a key suspect.

The school in Amrozi's village is a focus of the investigation

The breakthrough came last Tuesday, 5 November, when two trucks filled with police arrived suddenly in the dusty little village of Tenggulun, which lies in a barren and devoutly Islamic strip along the north-east coast of Java.

After questioning local residents, the officers made their way to the house of a 40-year-old car mechanic, Amrozi, who was living with his wife and parents.

He was whisked off to neighbouring Bali for interrogation.

White van

Two days later, the police announced that Amrozi was the owner of the white van used to carry the bomb which destroyed the Sari Club and that he was one of the main organisers of the operation.

Since then the police have been giving statements several times a day on the results of his interrogation.

Some of those statements have been vague, some confusing, but a picture of Amrozi's role is beginning to emerge.

Authorities say he has admitted to being the owner of the van, and to visiting a shop in the city of Surabaya to buy the chemicals used in the bomb. The shop owner is also being questioned.

Cleric connection

Details of the precise role Amrozi played in planting the bomb have not been revealed, but he did lead the police to a house in Denpasar where he stayed just before the bombing.

Mr Ba'asyir's detention has sparked protests

Traces of the explosive RDX, which was used in the attack on the Sari Club and Paddy's Bar, have been found there.

The police now say Amrozi has admitted meeting the Muslim preacher Abu Bakar Ba'asyir on several occasions - while Mr Ba'asyir was in exile in Malaysia in the 1990s and more recently after the preacher's return in 1998, when he was invited to speak at the small Al Islam school in Tenggulun.

Mr Ba'asyir, the head of a large Islamic school near the city of Solo, is currently being detained over his alleged involvement in other bombings in Indonesia.

He is accused by the Malaysian and Singaporean authorities of being a founder and spiritual leader of Jemaah Islamiah, a shadowy, regional network of militants thought to have attempted or carried out a number of attacks across South East Asia.

Mr Ba'asyir has denied the existence of Jemaah Islamiah, and says he does not remember meeting Amrozi - but Amrozi's testimony appears to contradict him.

Villagers recall

Villagers in Tenggulun have corroborated some of the police statements.

They say Amrozi left for Malaysia in the late 1980s - as many young Indonesian men did - in search of work, and returned in 1991 with much stronger Islamic beliefs.

After that he became much more involved in the Al Islam school, where about 150 students follow a strictly religious curriculum.

The villagers also remember occasional visits by Mr Ba'asyir. They confirmed that Amrozi made recent visits to Malaysia and Thailand, and that he had not been in the village at the time of the Bali bombing.

The police are still pursuing as many as nine of Amrozi's accomplices.

They have questioned three:

• The head of the Al Islam school
• A barber who cut Amrozi's hair twice in the past month - possibly in an attempt to disguise his appearance
• A man who helped strip valuable parts from the van before the Bali bombing

Amrozi apparently wanted to minimise the cost of his operation, which suggests he was not well funded.

What is not yet clear from Amrozi's interrogation is whether the Bali bombing was a locally planned operation or whether it was initiated by senior leaders of Jemaah Islamiah.

Still murky

Little is known about the organisation, or how it is structured.

The authorities in several South East Asian countries are still hunting the alleged leader of Jemaah Islamiah, Riduan Isamuddin, better known as Hambali.

Regional intelligence sources say a meeting of Jemaah Islamiah operatives took place in southern Thailand in January this year, at which they decided on a strategy of going after relatively easy Western targets such as tourist resorts.

Amrozi may be able to give a clearer picture of Jemaah Islamiah's role, if any, in the Bali bombing - but he has not done so yet.