Would the gain be illicit if the money invested in the project is of dubious provenance?

Dealing with a person who possesses unlawful wealth is divided into two categories: prohibited and disliked. It is prohibited if the transaction is directly with the unlawful wealth itself. It is disliked if their lawful wealth is mixed with their unlawful wealth. The questioner must ascertain the nature of the other person's earnings: if their wealth is purely unlawful, then dealing with them is prohibited; if it is suspicious or mixed, then it is disliked. If their work is based on deception, it is prohibited. However, if their work is brokerage under its specified conditions, it is permissible.