Karima Anjani and John M. Glionna, Tokyo and Jakarta – Three members of a civilian patrol that enforces Islam's strict Sharia law in Indonesia's Aceh province have been accused of gang-raping a 20-year-old university student, authorities there said.

The attack allegedly occurred this month at a small-town police station after the patrol members, known here as the Sharia police, took the woman into custody. Two men, ages 27 and 29, were arrested and one is still being sought, authorities said.

Activists say the accusation seriously undermines the credibility of the controversial Sharia police patrols.

"They don't have the authority to detain people – their role is to give moral advice, that's it," said Norma Manalu, director of Aceh's human rights coalition. "They misused their power."

Aceh's "vice and virtue patrol" enforces religious codes across the only province in the nation to employ Sharia, or Islamic law, for its criminal code. Indonesia is the world's most populous Muslim country.

Sharia was introduced in 2002 after the region was granted autonomy as part of efforts to end a decades-long guerrilla war. Supervisors say the Sharia police, formed three years later, consider themselves the community's public conscience.

In September, Aceh's provincial parliament passed a law saying that people who commit adultery can be sentenced to death by stoning. The measure, which still must be approved by the governor, has outraged human rights groups here, which say it will be used to unfairly target women.

The Sharia policemen allegedly stopped a couple by the road near a plantation. In an interview, the victim's father said his daughter's friend was beaten by the group and the couple was then brought to a nearby Sharia police station.

The men later returned while off duty and raped the woman, investigators say. "She was treated like an animal. They suffocated and raped her – it was inhumane," the victim's father said. "She's in deep trauma."

Marzuki Abdullah, head of the 1,500-member Sharia police force, said the case was not linked to the patrols because any crime the officers might have committed was done while they were off duty. Activists say the case should bring a review of the patrols.

"It's time for the Sharia police to introspect their institution, role and officers," said Manalu. "Are they really needed to judge our morality? We don't have any guarantees that they have a higher moral standard than us."