BANKERS BOOK EVIDENCE ACT, 1891, SECTION 6

Section-6

If any party to a legal proceeding made any application to a Court or to a Judge, such Court for Judge may direct for inspection of those documents or to take copies of any entries of the bankers books for the purpose of such proceeding. It is referred in the law that when a legal proceeding is pending. Only in connection of such legal proceeding and on such prayer, the court may order for inspection of such documents or for taking copies of entries but there is no provision either in section 5 or 6 of the Bankers Books Procedure enabling any police officer or an officer under the Bureau of Anti-Corruption for obtaining permission from the Court of Sessions for seizure of any banking document for the purpose of any inquiry before initiation of any legal proceeding.

Islami Bank Bangladesh Ltd. Vs. Dist. Anti-Corruption Office &  Anr. 11 BLT (HCD)-246.