Javed, a member of Press Club of India who had booked a hall on its premises for the event, was questioned for hours for the second consecutive day, a police official said.
All those who were present on the dais at the said event will be asked to join investigation at the earliest, the official added.
Delhi Police yesterday said they have booked Geelani and several unnamed persons in a case of sedition, criminal conspiracy and unlawful assembly in connection with the event in which "anti-India sloganeering" took place.
Police claimed Geelani was booked as he is presumed to be the main organiser of the event.
"Request for booking a hall at Press Club was done through Geelani's e-mail ID and the nature of the event was proposed to be a public meeting. We are monitoring video footage and trying to ascertain the identity of the ones involved in anti- India sloganeering," a senior official had said.