How and under what sections can a IO recover original documents

The Magistrate Court has order the IO to re-investigate the case under Section 173(8) in order to confiscate original sales/purchase deeds signed by the accused and 22 witnesses who have bought shops illegally from the accused persons. Chargesheet has been filed Us 402, 420, 504, 506 . Statement from 22 witnesses has been filed in the charge-sheet stating that the witnesses have bought shops from the accused persons by way of sale/purchase agreements and are also fully aware that the municipal taxes are in the name of the father of the accused persons and would also produce the said documents as and when required. The agreements are unregistered on Rs. 10/= stamp paper and cannot be obtained from any Govt agencies under RTI. The IO states that he can search the accused and witnesses but cant arrest them. They are all aware of the move and have removed all the documents from their premises. How should the IO recover these documents and under what sections of the CRPC and IPC