HONG KONG (AP) — Hong Kong police are investigating allegations that a 23-year-old Indonesian maid was tortured by her employers, the latest case to provoke outrage over abuses suffered by the city's army of foreign domestic workers.

A group representing Indonesian migrant workers in Hong Kong said Thursday that Erwiana Sulistyaningsih came to the city in May and suffered beatings until returning last week to Indonesia, where she's being treated in a hospital.

The family that employed Sulistyaningsih slapped and punched her every day, according to Sringatin, vice-chair of the Indonesian Migrant Workers Union. She said the employers let Sulistyaningsih go back to Indonesia when she could no longer work because of her injuries and gave her just 70 Hong Kong dollars ($9).

Sulistyaningsih needed a friend to help her at the airport because she couldn't walk properly, said Sringatin, who like many Indonesians uses one name.

The case came to light after pictures of Sulistyaningsih's injuries began circulating among Hong Kong's Indonesian community. The photos, which Sringatin said are genuine, show scabs and lacerations on Sulistyaningsih's face, hands and legs, and blackened skin around her feet.

Sulistyaningsih's employers were very strict and demanding, permitting her to sleep only four hours a day and insisting that she do the cleaning in a particular order, Sringatin said.

"But if Erwiana cleaned the toilet before cleaning the bedroom, the employer would beat her," Sringatin said. "When the employer called Erwiana and she didn't hear, the employer would also assault her."

Migrant worker groups in Hong Kong held two protests this week, including one on Thursday, to bring attention to the case and highlight what they called "modern day slavery."

In response to an inquiry about the case, police issued a statement saying they were investigating the allegations after receiving a complaint from a maid placement agency about abuse by an employer, without releasing any names.

Hong Kong's Labor Department said it has been in contact with the Indonesian consulate general in the city, the employment agency and domestic helper groups in relation to the case.

Indonesian Consulate spokesman Sam Aryadi said Sulistyaningsih was undergoing physical and psychological examinations in Indonesia, and that she may return to Hong Kong to help with the investigation.

There are about 312,000 foreign domestic workers in Hong Kong, with Indonesians accounting for about half and Filipinos making up most of the rest. Most are young women.

Last year, a couple was sent to prison for torturing their Indonesian maid with a hot iron, a paper cutter and a bicycle chain.

A report in November by Amnesty International slammed the Hong Kong and Indonesian governments for allowing conditions that left women working as maids vulnerable to widespread abuse and exploitation, including restrictions on freedom of movement, physical and sexual violence, lack of food and long working hours.