Malaysian lawyers, politicians and activists have lambasted the police, accusing them of abusing their power in chaining up and marking the bodies of 30 foreign women detained for alleged prostitution.
Police raided a high-end nightclub in northern Penang state late on Thursday and arrested 29 women from China and one from Vietnam, along with eight Malaysian men.
Local media reported police officers went undercover at the club for a week before the raid. It triggered an outcry after local newspapers carried photos of the women bound up with a long chain and marked with either a tick or an X on their chest and forehead.
"The police branded the detained women as though they are cattle," opposition politician Teresa Kok said in a statement. "It is sickening that the police would employ such dehumanising tactics as a show of power and moral superiority over their detainees."
Women's rights group Tenaganita said the detainees had been victimised and called for an investigation into the police conduct.
Another rights group, Lawyers for Liberty, said the police action was "very unusual and inhumane" as the women were merely suspects and not convicted of any crime.
Police have defended their action, saying the markings served as a way to identify the women.
Penang police chief Ayub Yaakob told the New Straits Times that the situation was chaotic, with the suspects trying to escape.
He said police were forced to mark the women after some donned new clothes to try and blend in with other female patrons of the club.
He also said the women had wrecked many marriages and that police had received numerous complaints from wives of men who sought their services.