With five closed-circuit television cameras pointing towards the walkway leading to the second-floor shophouse unit and a security door in place, staff at a facial spa on Upper Thomson Road should have been prepared for any visitors.
Yet three female employees and two of their male clients were caught off guard when the police came knocking - and discovered it was an unlicensed massage establishment.
The random enforcement check by officers from the Bishan Neighbourhood Police Centre was part of an intensive two-week islandwide operation targeting unlicensed and errant massage parlours.
The Singapore Police Force revealed yesterday that it arrested 10 women for offences under the Women's Charter and Employment of Foreign Manpower Act.
Fourteen massage parlours were also found to have been operating without a valid licence.
Officers checked 41 establishments across 15 neighbourhoods from March 1 to 14.
Police stepped up checks in the wake of the new Massage Establishments (ME) Act, which came into force on March 1, giving them more bite in weeding out unlicensed massage parlours and errant landlords.
Those who flout the law now will face significantly higher penalties like up to two years' jail and a maximum fine of $10,000. The ME Act also restricts operating hours for most licensed massage parlours.
Commanding officer for Bishan Neighbourhood Police Centre Michael Ben Chee said: "The new ME Act... will equip the police with stronger levers to deal with vice activities and law and order problems in massage establishments."
The number of unlicensed massage establishments detected by police increased by 40 per cent between 2013 and 2016.
There were about 300 such errant operators found in 2016, with 7 per cent operating in Housing Board properties and 40 per cent engaging in vice-related offences.
Some unlicensed spas operate 24 hours and provide sexual services, often near HDB flats.
Although the establishment visited by officers in Upper Thomson Road is meant to be a facial spa, a massage bed was found in one of its rooms. Journalists were allowed into the premises during the two-hour enforcement operation.
Three foreign women - two wearing short dresses and one in denim shorts and a T-shirt - were overheard explaining to the police the nature of their work at the spa. Officers checked the other rooms for incriminating evidence. In one room was a tablet showing five "live" camera views of the walkway outside.
The women's immigration documents and work permits were all in order but, while no arrests were made, the facial spa was found to have provided unlicensed massages.
That same day - March 8 - Tanglin Division officers checked six massage outlets during enforcement operations. No arrests were made but three outlets were found to have provided unlicensed massage services.
Investigations against the operators will ensue, police said.