Jakarta. Lawyers representing firebrand Islamic Defenders Front cleric Rizieq Shihab have urged the authorities to terminate an investigation into a pornography case allegedly involving him, due to "invalid evidence."

For weeks Rizieq has been fleeing the investigation. He is charged with engaging in pornographic WhatsApp chats, which is an offense under Indonesia's strict anti-pornography law.

Police say they have collected sufficient evidence to name Rizieq a suspect in the case, but lawyer Kapitra Ampera said they have done so illegally.

"The evidence in Rizieq's case has been obtained illegally, through wiretapping by unauthorized parties. Thus it cannot be used as valid evidence in the investigation or in a court trial," he said in a statement on Tuesday (21/06), adding that Rizieq's legal team calls on the president to instruct the police to terminate the investigation.

Police have said, however, they will press ahead with the investigation and are seeking ways to bring Rizieq back home. He is currently in Saudi Arabia and, according to his legal team, will not return to Indonesia anytime soon.

Last month, police named Firza Husein, the woman who allegedly sent nude pictures of herself to Rizieq in the chats, a suspect in the case. Under Indonesia's Electronic Information and Transactions (ITE) Law, both can face at least five years in prison, if convicted.

Those who had leaked the chats to the internet have not been identified yet, despite the police promising to do so weeks ago.