National Investigation Agency has issued a notice to controversial Islamic preacher Zakir Naik asking him to appear before the agency at its headquarters in Delhi on 14th of this month.<br/> <br/>The notice was served at Naik's Mumbai-based residence. The founder of Islamic Research Foundation has been booked under Unlawful Activities Prevention Act for allegedly promoting enmity between different groups on grounds of religion.<br/> <br/>Meanwhile, Naik's sister Nailah Noorani was questioned by Enforcement Directorate (ED) today about the alleged fund transactions in her account and the firms associated with her.<br/> <br/>The ED was looking into the charges of alleged laundering of illegal funds by Zakir Naik and the subsequent proceeds of crime thus generated. The central probe agency had registered a criminal case against 51-year-old Naik in December last year after taking cognisance of NIA's complaint.