Ansari has been kept in a high security barrack, they said.
Ansari had been taken to Mumbai in December 2008 by the Mumbai ATS in the wake of the terror attack there.
He was acquitted recently by a Mumbai court in the terror attack case in the absence of adequate evidence.
Seven CRPF jawans were among nine people killed in a terror attack on the CRPF group centre at Rampur on Jan 31, 2007, and nine people, including Fahim Ansari and Sabauddin, were arrested in connection with the case.
Before being taken to Mumbai in connection with the terror strike case, Ansari was lodged at the Bareilly jail.
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