Former students of an Islamic boarding school on Indonesia’s Lombok island spent years collecting accounts from classmates who alleged sexual abuse by their former head teacher, Ahmad Imanuddin Sumar, known as “Abah”. The BBC reports that the investigation was led by former pupils Yusron Azzahidi and Ziadatur Rahmah, who had both been high-achieving students at the school.

The investigation began after Ziadatur told Yusron that Sumar had sexually assaulted her when she was 16. She later described to the BBC how he allegedly took her to his house on the school grounds, where she said he kissed and touched her before she escaped when one of his children knocked on the door. Other former students then shared accounts, including Sukma Rohana, who said Sumar tried to rape her when she was 17.

Yusron coordinated the accounts and prepared a seven-page document describing allegations involving Ziadatur, Sukma and four other former students. Wanda Hamidah arranged a meeting with representatives of Nahdlatul Wathan Diniyah Islamiyah, or NWDI, the organisation that ran the school and other institutions. The students said representatives initially promised to help take the matter to police.

According to the BBC, the documents were later passed to Sumar. Yusron recorded a phone call in which the former head teacher allegedly urged him to stay silent and offered explanations he could use to retract the document. Ziadatur also recorded a call in which, the BBC says, Sumar admitted abusing her while asking her not to disclose it.

Sukma told the BBC that she was summoned to Sumar’s house and found two police officers and an NWDI lawyer there. She said she was pressured to sign a statement declaring her allegations false. A recording she later made of a conversation with Sumar’s wife is cited by the BBC as supporting her account of the pressure.

Yusron eventually halted the investigation after pressure extended to his family. The BBC says the wider investigation will examine the allegations and the students’ efforts to seek justice. Sexual abuse in Islamic boarding schools has been described as a national emergency by Indonesia’s National Commission on Violence Against Women, while legal experts say many cases do not reach court because victims are persuaded or pressured to withdraw them.