NEW DELHI: Tablighi Jamaat chief Maulana Saad has written to the Delhi Police , demanding a copy of the FIR registered in connection with an event at Markaz mosque in Nizamuddin."I have already joined the investigation by replying to two notices under Section 91 Cr.P.C dated April 1, 2020, and April 2, 2020, both issued by your good office," he wrote in the letter.