After his religious boarding school sparked demonstrations for allowing women to lecture and offer prayers alongside men, a Muslim preacher has been detained on suspicion of blasphemy and hate speech, authorities announced Wednesday.

The Al-Zaytun boarding school in West Java, the most populous region of Muslim-majority Indonesia, has come under fire from religious groups who claim it practises a kind of Islam that is incompatible with the Holy Quran.

After being questioned, 77-year-old school principal Panji Gumilang was taken into custody early on Wednesday, national police spokesman Ahmad Ramadhan informed reporters.

“Investigators took legal action and he is detained in the criminal investigation agency’s detention facility for 20 days,” he said.

Gumilang faces five years in prison for blasphemy, six for spreading hate speech and 10 on the charge of spreading fake news and intentionally causing chaos in public, according to the charges.

The school sparked uproar in religious circles and protests outside its compound when social media footage in late April showed women praying in the same row as men.

According to traditional Islamic prayer, women are typically expected to pray behind men.

Another practice of the school that sparked controversy was allowing women to give a sermon in Friday prayers, a task usually reserved for men according to traditional Islamic teaching.

The school which was established in 1999 and holds around 5,000 students is also accused of ties to Darul Islam, a group that fought for an Islamic state in Indonesia in the 1950s and 1960s and survived a military defeat, AFP reported.

Thousands have gathered outside the school several times since late June to call for its closure.

Indonesia’s blasphemy legislation has been on the statute books since 1965 but was rarely used before the end of authoritarian rule under dictator Suharto in 1998.

However, rights activists say the blasphemy law curbs free speech and puts religious freedom under increased pressure.

Indonesia recognises six official religions but the growing use of the blasphemy law is fuelling fears that its moderate brand of Islam was coming under threat from increasingly influential radicals, according to AFP.

Additionally, Jakarta’s former governor, the capital’s first Christian leader of Chinese descent, was sentenced in 2017 to two years in jail for blasphemy.