What is the ruling on investing money, the origin of which is doubtful - due to suspicion of usury - with the intention of expelling this origin after the money has grown?

As long as the company gives a fixed amount or a percentage added to the principal, it is clear usurious interest, and it is not permissible to invest money in it. The money must be withdrawn from it, and the usurious interest must be disposed of by spending it on the welfare of Muslims or giving it to the poor and needy. It is not permissible to delay repentance from usury and getting rid of unlawful money, because death may surprise a person before he can dispose of it.