Suspected brothels have popped up in a Katong private housing district for the second time in 2015.
Residents reported that suspicious activities have been spotted at four of the six bungalows on Crescent Road.
One of the bungalows was raided by the police on April 28, and two woman were cuffed and detained, according to past reports.
Residents, who did not wish to be named, told Chinese daily Lianhe Wanbao that barely a month later, foreign workers had moved into the bungalows.
They then spotted men loitering around the area, sending messages and checking their mobile phones.
After a while, they would walk into one of the bungalows.
A resident said that at noon on Sunday, he saw a woman in heels climb over the perimeter wall into one of the bungalows.
Another resident said that a man once rang their doorbell at 2am, and asked if they provided sexual services.
They said that the men who frequented the suspected brothels in the past seemed affluent, and some even had chauffeurs.
The men spotted loitering nearby recently, appeared less well-off.
Residents said they have reported the matter to the police and to their Member of Parliament.