If the leader does not pay by the due date and if the amount cannot be offset in accordance with  Article II.21.2 (a), the contracting authority may claim the full amount to any other member of the group by  notifying the debit note already sent to the leader under Article II.21.2.  II.22. CHECKS AND AUDITS  II.22.1 The contracting authority and the European Anti-Fraud Office (OLAF) may check or require an  audit on the implementation of the FWC. This may be carried out either by OLAF’s own staff or by  any outside body authorised to do so on its behalf.  II.22.2 The contractor must keep all original documents stored on any appropriate medium, including  digitised originals if authorised under national law, for a period of five years starting from the  payment of the balance of the last specific contract issued under the FWC.  II.22.3 The contractor must grant the contracting authority’s staff and outside personnel authorised by the  contracting authority the appropriate right of access to sites and premises where the FWC is  implemented and to all the information, including information in electronic format, needed to  conduct such checks and audits. The contractor must ensure that the information is readily  available at the moment of the check or audit and, if so requested, that information is handed over  in an appropriate format.  II.22.4 On the basis of the findings made during the audit, a provisional report is drawn up. The  contracting authority or its authorised representative must send it to the contractor, who has 30  days following the date of receipt to submit observations. The contractor must receive the final  report within 60 days following the expiry of the deadline to submit observations.  II.22.5  In accordance with Council Regulation (Euratom, EC) No. 2185/96 of 11 November 1996  concerning on-the-spot checks and inspection carried out by the Commission in order to protect the  European Union’ financial interests against fraud and other irregularities and Regulation (EU,  Euratom) No. 883/2013 of the European Parliament and of the Council of 11 September 2013  concerning investigations conducted by the European Anti-Fraud Office, the European Anti-Fraud  Office may carry out investigations, including on the spot checks and inspections, to establish  whether there has been fraud, corruption or any other illegal activity under the contract affecting the  financial interests of the Union. Findings arising from an investigation may lead to criminal  prosecution under national law.  Such checks and audits may be initiated at any moment during the provision of the  supplies/services and up to five years starting from the payment of the balance of the last specific  contract issued under the FWC.  The audit procedure is initiated on the date of receipt of the relevant letter sent by the contracting  authority. Audits are carried out on a confidential basis.  On the basis of the final audit findings, the contracting authority may recover all or part of the  payments made in accordance with Article II.21 and may take any other measures which it  considers necessary.  The investigations may be carried out at any moment during the performance of the contract and  up to five years starting from the payment of the balance of the last specific contract issued under  the FWC.  34 