JAKARTA, Indonesia — In Indonesia, a public figure caught up in a scandal involving pornography or an extramarital affair would usually expect to be denounced by the Islamic Defenders Front, an influential hard-line Muslim organization.

This week, however, the public figure at the center of a scandal is Rizieq Shihab — leader of the Islamic Defenders Front.

The Indonesian police said on Monday that Mr. Rizieq would be charged with violating Indonesia’s pornography laws, weeks after screen captures emerged of sexually explicit text messages, purportedly between Mr. Rizieq and a woman who is not his wife.

Mr. Rizieq has denied that the text messages are real, and many of his supporters contend that he was framed by the Indonesian government. His Islamist movement rattled the government this year by leading a successful campaign to prosecute on blasphemy charges Basuki Tjahaja Purnama, a Christian and an ally of President Joko Widodo’s who until recently was governor of Jakarta.