SINGAPORE — At 2am early on Tuesday (Jan 17), two cars approached Catholic Centre on Waterloo Street and a group of about eight people alighted and started spraying an unidentified liquid and scattering a white substance around the building.

This was what closed-circuit television (CCTV) cameras caught, two staff members at the religious centre told TODAY.

In response to queries from TODAY, the police said that two men and nine women, aged between 49 and 67, are assisting in ongoing investigations. Early findings suggested that the case was linked to a similar one along Armenian Street, they added, referring to Bible House.

The incident at Catholic Centre was reported a day after a police report was made on Tuesday by Bible House, another religious centre.

The Singapore Civil Defence Force (SCDF) said in a statement to the media that at about 9.55am on Wednesday, it was alerted to an incident at 55 Waterloo Street, the location of Catholic Centre.

"Upon arrival, some white substances were found on the premises,” it said.

Wearing personal protective equipment, SCDF’s hazardous materials (HazMat) specialists retrieved some of the substances and conducted several tests.

"No harmful substances were detected,” it added.

For Bible House, the police said that they were alerted on Tuesday at about 11.40am to a case of "white substance found at a location along Armenian Street”.

Staff members there also confirmed that there was a white substance found along the building perimeters that day.

What CCTV footage shows

At Catholic Centre, the staff members who knew of the CCTV footage said that the recording clearly showed the faces of the people as well as the licence-plate numbers of the vehicles that pulled up to the nine-storey building.

The staff members spoke on condition of anonymity because they were not authorised to speak to the media.

"One person was preparing the powder and another person was taking a picture of the person,” one of the staff members who had seen the CCTV footage said.

There were about seven to eight people, with four females and three to four males, from what he could see.

He added that other than the powder being scattered, the group also appeared to spray an unknown liquid around the building, which he guessed had led the dark stains to form.

The white substance and unknown liquid was first seen in daylight on Tuesday when people reported for work. It was after this that CCTV footage was reviewed and a police report was made on Wednesday morning.

This led to a convoy of about five police cars and five fire engines arriving shortly after, and a section of the street was closed to traffic.

SCDF personnel wore protective HazMat gear to retrieve samples of the substance and powder.

When TODAY arrived at Catholic Centre at about 4pm on Wednesday, dark splotches were seen along the floor directly in front of the centre, with more of such stains and streaks on the walls at the side of the building.

Shortly after that, a maintenance worker put out safety cones near the building entrance where the dark splotches were, and also two "cleaning in progress” signs.

Another staff member who spoke on condition of anonymity said that she was told at about 11am on Wednesday to leave the building after SCDF came on the scene. She went to a nearby coffee shop with her colleagues to await further instructions.

She said that the stains on the floor were inconspicuous because she did not notice them at all the day before and saw them only when it was pointed out to her on Wednesday.

"Some staff had seen a white substance, some powder, but then the maintenance workers were sweeping it away, they didn’t know. But later on, they found out from the cameras that two cars came and (people were spreading) the substance around the whole building,” she said.

After more than an hour, they were told that the substance was harmless and that everyone could return to the building, she added.

"We had to wait for them to finish the testing (on the substance), to see whether it was anything bad.”

As far as she knew, no one reported any symptoms or felt sick.

Responding to queries from TODAY, the Roman Catholic Archdiocese of Singapore said it understood that the police and SCDF were investigating the case but it was unable to comment further.

Over at Bible House, which is about 600m from Catholic Centre, TODAY also noticed several small dark stains outside the building.

A staff member was said to have made a police report. A worker there asked reporters not to conduct interviews with any more of the employees because the matter was still under investigation.

TODAY has reached out to the Singapore Bible Society, which runs Bible House, for official comment. — TODAY