They were blatantly advertising their sexual services on the Internet.
While they wanted to lure men in, they did not expect the men in blue to show up last Wednesday evening.
The New Paper on Sunday was allowed to accompany officers from the Central Police Division in the raids.
Six alleged prostitutes from China were arrested in a Little India condominium.
Operating from two units there, the six bedrooms that were raided were obviously used for illicit activities - condoms were laid out on the beds and one of the women had more than 100 beside her.
Tubes of lubricant were spotted in almost every bedroom and on top of the normal bedlinen, thick towels were also spread out on the beds.
One of the women, a 26-year-old, said that she had left her husband and child behind in China to work as a prostitute here. She said that she charged $100 per session.
"I come from a very poor family and my husband doesn't know I work as a prostitute here," she said.
While none of the six women were underage, the youngest person the police arrested in the week-long operation was a 15-year-old foreign girl for vice-related activities.
The operation was part of an ongoing enforcement effort to crack down on illegal activities.
Prior to this, there were at least 14 other reported cases of police raids since January.
For this latest operation, about 200 officers raided places such as public entertainment outlets, massage establishments and private apartments in places like Little India, Chinatown and the Central Business District.
The officers busted two online vice syndicates and four illegal gambling dens.
They also arrested 409 people in all - 331 women and 78 men who are between 15 and 82 years old. They were caught for offences including illegal employment, unlicensed moneylending and illegal punting.
The oldest person arrested was a Singaporean man, caught for gambling-related offences.
Besides locals and Chinese nationals, the suspects came from Vietnam, Cambodia, Thailand and Malaysia.