Village officials have long been suspicious of school, occupants
Pondok Pesantren Ibnu Mas'ud is tucked deep in the hills near Mount Salak, an eroded volcano in Indonesia, not far from Bogor city in West Java province.
The pesantren, or Islamic boarding school, in Sukajaya village is not on many maps. It is accessible only by a steep mountain dirt trail barely wide enough for a small car or pick-up truck.
Locals, however, know it well because of its white-washed perimeter walls and the wrought-iron gate that secures a handful of buildings in the compound.
Ibnu Mas'ud was in the cross hairs of Indonesia's counter-terrorism forces after the Jan 14 attack in Jakarta, purportedly due to its ties to jailed cleric and radical ideologue Aman Abdurrahman. He was said to have ordered the terror attack from Nusakambangan prison.
Heavily armed commandos from Detachment 88 - also known as Densus 88, the Indonesian police's elite counter-terrorism unit - raided the complex the day after the siege on the capital.
The police did not say if anyone was arrested during that operation.
However, researchers from the Centre for Radicalism and Deradicalisation Studies now believe the school is home to many supporters of the Middle Eastern terror group Islamic State in Iraq and Syria (ISIS). At least a dozen of them have travelled to Syria to join elements of the group.
Three members of its staff and a teenage student were stopped in Singapore and sent home on Feb 21.
They "were deported to Indonesia after investigations revealed they had plans to make their way to Syria to fight for ISIS", said Singapore's Ministry of Home Affairs two days later.
However, Mukhlis Khoirur Rofiq, 22, his brother Muhammad Mufid Murtadho, 15, Risno, 27, and Untung Sugema Mardjuk, 48, were released on Feb 24.
All four were questioned by Densus 88, but they could not be detained further because, under the country's anti-terror laws, they did not commit any offence.
The Sunday Times visited Ibnu Mas'ud last week and met Mr Jumadi, a staff member who said he handles the school's community relations. Mr Jumadi, who goes by a single name, confirmed that the four were from Ibnu Mas'ud, but claims he was not aware of their plan to travel to Syria. He said they were in Singapore and Malaysia to "jalan jalan" or go on a tour.
When asked if they have been radicalised, he said: "If they are radicals, the authorities would not have let them go, and I also don't believe they wanted to join ISIS."
Mr Jumadi, however, also said the four have since been expelled from the school. He earlier claimed they have not returned since they left in mid-February.
He also refused to explain why they were kicked out and declined to answer when asked about the school's leadership and funding.
He said the curriculum at Ibnu Mas'ud covers basic mathematics, the Quran and the Hadith, a collection of sayings of Prophet Muhammad. Mr Jumadi added that the co-ed school has 180 boarders between five and 15 years old.
It can take in 80 more students once the construction of a new block is completed.
When The Sunday Times arrived at the school last week, afternoon prayers were in full swing in what looked like a newly built mushola, or small mosque, within its grounds.
The school's concrete complex was in stark contrast to the rest of the village, which is mainly comprised of rickety wooden houses.
There was a Honda Jazz hatchback and a pick-up truck - both spanking new - parked in the compound guarded by a young watchman who registered all visitors.
Ibnu Mas'ud stands out in the community not only because it is relatively well constructed and new - it was built in 2012 - but also because all its boarders and staff are from out of town, said Mr Ajud, head of residents' affairs in Sukajaya village, which has a population of about 10,600.
"The pesantren is not open to locals, but neither are any of the parents here keen to send their children to the school because it does not follow a formal education system," he said.
There also seems to be a high turnover of teachers at the school, added Mr Ajud, who oversees the registration of newcomers in the village.
"Since it was established, 98 teachers from East Java, Central Java and all over have come and gone," he said.
Village officials like Mr Ajud and Mr Udin Leo, who is in charge of civil security in Sukajaya, have long been suspicious of Ibnu Mas'ud and its adult occupants.
Mr Udin said he had tried to block the school's construction years earlier after its founders refused to answer some questions on its teachings and leadership.
He said he is not surprised that people from the school are linked to terrorism.
"I know this villager named Acong who did time in prison for burglary," Mr Udin recalled.
"Three years ago, when Acong and I were walking by the school, someone from the inside called out to him.
"When I asked him later how they knew each other, Acong said they were together in prison and the man who called out to him from Ibnu Mas'ud was a convicted bomb-maker."