Plenty of things aren't necessarily evidences. Just because you have access to account statements telling you you got a bunch of money coming in from person X for provision of service Y and a matching contract doesn't mean that the contract has been fulfilled or that the service was worth the money.
Same with picking a supplier - there are processes in place that try to assess quality, speed, price, effort, etc, but in the end it's humans making decisions, humans with bias and the ability to lie and make untrue statements as to how they made their decision.
Then there are the usual money laundering techniques, eg art dealing. You could easily spend a few million $$ on art for, say, a big office. And the VP's niece might be an artist that can demand that on the open market.
Same with picking a supplier - there are processes in place that try to assess quality, speed, price, effort, etc, but in the end it's humans making decisions, humans with bias and the ability to lie and make untrue statements as to how they made their decision.
Then there are the usual money laundering techniques, eg art dealing. You could easily spend a few million $$ on art for, say, a big office. And the VP's niece might be an artist that can demand that on the open market.