The Bihar police have arrested six people, including the mother and sister of the key associate of a dreaded north Bihar gangster, in raids conducted in connection with the kidnapping of Delhi Public School student Kislay.

They have also detained the wife of Chunnu Thakur, who is lodged in Hajipur jail, for interrogation.

Senior superintendent of Police (Patna) Nayyer Hasnain Khan told PTI that the mother and sister of Vicky, the right hand man of Thakur, were picked up from Chakia village in East Champaran district on Friday night.

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Earlier, the police had detained Thakur's wife Kiran from her Gannipur residence on Thursday night.

Four other criminals were also arrested earlier from Patna, the SSP said but did not disclose their identities.

Kislay, son of Sales Tax Assistant Commissioner K K Gupta, was abducted from near his Patel Nagar house on January 19 when he was on way to board the school bus.

His abduction sparked off a series of protests, and school children held a protest demonstration in front of the Raj Bhavan in Pata on Friday. They met Governor Buta Singh seeking his intervention to secure the safe release of Kislay and two other students, who were also kidnapped recently.

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Ravikant, a student of DAV public school, Biharsharif, was kidnapped on January 24, while Dipak Kumar, student of DAV Public School, Bhagalpur, went missing a day later.

Students took out a protest march in Bhagalpur on Saturday and submitted to the district magistrate a memorandum addressed to President A P J Abdul Kalam seeking his intervention for the release of Dipak.