Hi Alex, I'm not questioning your actions in any way, I'm just hoping for some clarifications.
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The nominee had a meeting with the lawyer. In one's turn the lawyer also had a chance to get familiar with the details of the international police order.
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Please elaborate on this if possible. What does the police order compel, to which party is it directed, and which alleged crime is it based on, if any?
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2) The user lies. "this was a coincidence and came from one of the exchanges we have used" - it is obvious and well known that crypto=>fiat exchange does not function as a mixer and has one fiat "output". The entry point was the crypto which you have sent to the exchange. The exit point was the fiat funds sent to the debit card which has been used by you at that particular point of time. You are trying to veil your fault.
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Just to be clear; are you suggesting that your customer's crypto address in this case was suspected by the police to be connected to some crime or criminal, and that they (Interpol) waited for it to be the source in a transaction to an enforcable party such as the exchange in question? In that case, how did the police connect the receive address with the specific exchange in question, does the exchange re-use receive addresses?