The National Investigation Agency, which took over the case, produced the crew members before the NIA court here.
After initial hearing, the court sent them to the Kakkanad district jail till August 13.
Last week, the NIA had filed the First Information Report in the case.
The 12-member crew of 'Barooki', which was intercepted by Coast Guards off Alappuzha waters, had been arrested by Kerala Police.
According to preliminary investigation, all the crew members were believed to be Iranians.
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A joint interrogation of the crew by various agencies, including RAW, had been conducted.
The crew had left from Kalat in Iran on May 25.
The dhow was intercepted by Coast Guards and the state police following intelligence inputs regarding the boat off Alappuzha and it was brought to Vizhinjam on July 5.