Trouble seems to be growing for Mumbai-based controversial Islamic preacher Zakir Naik. The televangelist who is accused of inspiring a number of people to join ISIS might be slapped with terror charges. The union home ministry has decided to book Naik under the Unlawful Activities Prevention Act (UAPA) for his speeches. "The primary ground for invoking terror charges against Naik are statements by those involved in past terror acts, conceding that they were motivated by his speeches," said an intelligence officer.

His organisation, the Islamic Research Foundation (IRF), which is in the midst of controversy over alleged "forced conversions" also could be booked under the UAPA and faces closure.

The organisation's activities had come under the scanner after the brother of one of the over-a-dozen Kerala youth who are believed to have joined IS alleged that he was forced by an IRF member to come to Mumbai for conversion.

Two associates of Naik, Arshi Qureshi and Rizwan Khan have already been booked by Mumbai police under UAPA after the father of Ashfaque Kader Ahmed, one of the missing Kerala youth, lodged a complaint claiming that his son was radicalised by the duo to join IS.

Once IRF and its associate organisations are declared as 'unlawful', it will face closure of its offices and interests across the country. Apart from having its head office at Mumbai, IRF runs the Islamic International School in Mumbai and Chennai through the IRF Educational Trust and owns many properties in Mumbai.

The government has also banned the broadcast of Naik's TV channel, Peace TV. The controversial scholar who was in Saudi at the time of the Dhaka terror attack, of which two of the terrorists were allegedly his followers, has refused to return to India, while claiming that he did not inspire anyone to join any terrorist organisation, and termed ISIS unislamic.