Is the money taken in exchange for helping an electrician win a bid for network installation in the questioner's company, along with supervising the execution and sharing the profits with him, unlawful money, and to whom should it be returned if it is?

You are an agent for the company, not a broker, and any increase you earn belongs to your principal. You are not permitted to take this money unless there is a prior agreement with the company on a specific brokerage fee for the client. If the agreement was for a percentage, then the lease is void, and you are entitled to a customary wage. In the absence of an agreement, the money you took belongs to the client if the company was the one who agreed with them on the fee. However, if you were the one who agreed with the client as an agent for the company, then the money belongs to the company.