The latest suspect arrested in connection with the plot to fire a rocket at Marina Bay from Batam planned to work as a cleaner on Sentosa island in Singapore.
Investigations are now under way to establish if the Sentosa work arrangement was related to the Batam-based militant cell, which the suspect is believed to be a member of, or to other terror activities.
Riau Islands police chief Sam Budigusdian said yesterday that the 24-year-old Indonesian confessed during questioning that he had arranged to make the trip to Singapore with five other people.
"They were using an illegal employment agency, but they would go to Singapore using legal channels," said General Sam.
The general, however, did not reveal the identity of the others or comment on when they had planned to leave for Singapore.
The latest arrest was conducted by Detachment 88 counterterrorism officers, who nabbed the young man at an Internet cafe in Batu Aji in Batam on Saturday morning.
The officers also seized an airsoft replica of an assault rifle, two mobile phones, an Indonesian passport and a travel itinerary that showed Singapore as the destination during a search of the suspect's home at the Carina housing estate.
The police referred to the suspect only by the initials LH, but a community leader identified him yesterday as Leonardus Hutajulu.
Leonardus, a Batak from North Sumatra, is believed to be a member of the terrorist cell in Batam led by 31-year-old factory worker Gigih Rahmat Dewa, the point-man behind the foiled rocket attack.
Gigih had planned the rocket attack under the direction of Bahrun Naim, an Indonesian militant believed to be in the Middle East fighting for the Islamic State in Iraq and Syria (ISIS).
According to the police, the plot was thwarted after Gigih and four members of his cell were arrested in Batam on Aug 5 by Detachment 88. Follow-up raids at their homes found weapons such as a bow and arrow and an airsoft gun modified to resemble an AK-47 assault rifle, but no rocket was found.
Gen Sam said investigators uncovered evidence that Gigih was training operatives for the attack on Marina Bay, and had marked out potential launch sites for the rocket which he intended to fire from Batam's "outer islands".
"The group had been measuring elevation points, conducting training exercises intensively and measuring the distance for a rocket launch," said Gen Sam.
The police said Leonardus had joined other members of Gigih's cell for drills using airsoft guns in preparation to fight alongside ISIS militants in Syria.
The group is also suspected of helping Indonesians travel to Syria, and harbouring Uighur militants in Batam.
Gen Sam said Gigih and his men would be prosecuted under Indonesia's anti-terrorism laws and face jail terms of up to 20 years each if found guilty.
In a related development, national police chief Tito Karnavian told Parliament yesterday that the 17-year-old who tried to blow himself up inside a Catholic church in Medan on Aug 28 had also been in touch with Bahrun Naim in Syria.
"He directly contacted Bahrun Naim who is in Raqqa, Syria," said the four-star general.
Ivan Ahmadi Hasugian attacked the priest with an axe after he failed to blow himself up in the church, but he was stopped by members in the congregation.
Six bombs assembled by the teenager were found in his backpack along with a message that read "I love al-Baghdadi", reported Xinhua news agency yesterday. Abu Bakr al-Baghdadi is the leader of ISIS.
General Tito described Ivan's recruitment by Bahrun Naim as a "new phenomenon" in Indonesia.
