According to The U.S. Department of Justice, the evidence of money laundering may be either direct or circumstantial, but it must prove these aspects of illegal activity.
The prosecutor does not have to prove that you performed a financial transaction, but there must be evidence that you at least participated in the attempt to perform a financial transaction. This could include a sale or purchase, a loan, a gift or a transfer. The transaction must affect commerce between states or internationally and involve wire transfers, money or property, or use a financial institution that affects commerce between states or internationally.
Proving that you intended to participate in a money laundering offense may be more difficult than proving the initiation, conclusion or attempt to carry out a financial transaction. Your intent could be clear if the prosecutor can show that you knew the money, property or other asset came from the committing of a felony at the federal or state level, or from the violation of a foreign law. It does not matter whether you are aware of what the offense or violation is. It only matters that you know that the asset is the proceeds of an illegal action.
The prosecutor does not have to prove that you knew the asset came from an illegal activity if he or she can show that you intend to use the funds for illegal purposes, or that you know that someone else intends to use the funds illegally.