To trace related-party transactions and particular steps they include, as well as the initiator of those transactions, the State Revenue Service (SRS) uses a variety of methods for obtaining information. We have discovered that as part of tax controls, silent administrative cooperation appears to occur in how information on the actual existence of transactions is exchanged. To obtain objective arguments and evidence and to identify the actual proceedings of transactions, the SRS requests explanations from persons named in documents supporting the transactions, including from the taxpayer’s former employees. In this article we explore how this cooperation takes place.