According to the court sources, District Judge Amarnath extended the period after the National Investigation Agency (NIA) told the court that the probe in the case was still on to unravel the larger conspiracy.
"The investigation in the instant case is spread in different parts of the country and abroad the larger conspiracy of IS activities is yet to be ascertained," the agency told the court, adding that more time was required for completion of the probe.
"The identity involved of such associates is being ascertained on day to day basis," the agency said.
It further told the court that mobile phone sets, SIMs, laptops and micro SD cards recovered by Delhi police from the possession of the accused persons, have been sent for forensic analysis and reports are still awaited.
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The bail plea, moved by advocate M S Khan, had claimed that further custody of the accused was not required.
Sayyed was produced before the court after expiry of his judicial remand.
The four arrested co-accused -- Akhlakur Rehman, Mohd Osama, Mohd Azeemushan and Mohd Mehraz -- were alleged to have told their interrogators that they had come into contact with Yusuf through Facebook and other chat platforms and he had motivated them for propagating violent 'Jihad' in India.
All of them were found to have links with a former Indian Mujahideen (IM) terrorist who later went to fight for ISIS, the agency had claimed.