The Batam terror cell whose leader was plotting to fire a rocket into Singapore's Marina Bay avoided suspicion by training openly with replica guns in a field near a housing estate.
Its five members, including leader Gigih Rahmat Dewa, 31, would gather in a field in Nongsa district to practise handling weapons, Batam district police chief Helmy Santika told The Straits Times by phone yesterday.
The little-known cell is called Katibah GR, or "Cell GR".
"Unlike other terror groups which train in the forests, they exercised and practised handling airsoft guns (a type of replica gun) in a field near a housing estate," he said.
"In that way, people were not suspicious of them."
The new details emerged after police confirmed that the five suspects had been flown to Jakarta on Tuesday, four days after their arrest, for further investigations.
Commissioner Helmy said all evidence, such as weapons seized in raids, had also been sent to Jakarta. "They (the five men) were tightly guarded by police in Riau as well as from Densus 88, all of them fully armed," he said, referring to the country's elite counter- terrorism police unit.
Separately, national police spokesman Agus Rianto told The Straits Times that the men will be questioned by Densus 88 investigators for involvement in terror.
Police are continuing to track down other members of Gigih's cell on the island as well as in other parts of Indonesia, he added.
The five Batam men, aged 20 to 46, are accused of sheltering two suspected Uighur militants.
Gigih also allegedly received and channelled funds for radical activities and aided Indonesians to go to Syria to join the Islamic State in Iraq and Syria terrorist group.
Mr Helmy also revealed yesterday that one of the Uighurs, identified only as Doni, had entered Batam from Singapore by sea around last March or April. He was deported to China after his arrest.
"We are not sure how he got to Singapore, whether he had used a fake passport or through illegal means," he said.
He also said Batam police have met the Singapore authorities to work out "more intensive cooperation and exchange of information".
"We want to make sure people here feel secure, not only Batam residents, but also the many Singaporeans here," he said.
Police have so far seized bomb- making materials and weapons from the homes of the suspects. These included a bow-and-arrow set, two airsoft guns, one of which had been modified to resemble an AK-47 assault rifle, and an air rifle.
Police said previously that the cell members had received online training via Facebook chats from Syria-based Indonesian militant Bahrun Naim to "assemble firearms, make explosives and build that rocket".
They also said the men had received training in handling firearms and set up a command structure, with Gigih appointed the group's "amir", or commander.