Jakarta. Firza Husein, a key witness in an ongoing pornography case allegedly implicating firebrand Islamist cleric Rizieq Shihab, remained tight-lipped as she underwent interrogation by Jakarta Police on Tuesday (16/05).

Her friend, only known as Emma, was also questioned by police in matters related to the investigation.

Tuesday's interrogation comes as Rizieq, leader of the hardline Islamic Defenders' Front, remains defiant in complying with police summonses related to the investigation, in which screenshots of a pornographic conversation allegedly between the cleric and Firza went viral on social media.

"Later, please," Firza said upon arrival at the Jakarta Police headquarters in response to reporters' questions.

Firza allegedly sent naked pictures of herself to Rizieq on the popular mobile messaging application WhatsApp, while an alleged phone conversation between Firza and Emma about Rizieq was also posted to social media.

Jakarta Police spokesman Sr. Comr. Argo Yuwono said Emma underwent brief interrogation, though was only asked "one or two questions."

Rizieq, who was initially reported to police for allegedly violating the 2008 Information and Electronic Transactions (ITE) law, failed to comply with two earlier police summonses.

Police last week said they plan to take Rizieq by force once he returns to Indonesia from traveling abroad.