How is money stolen from a relative repaid after it has been invested and grown with lawful funds?

The profit arising from investing stolen money is a matter of dispute, and the most equitable opinion is that it should be shared equally between the owner of the money and the thief. Thus, the thief must ascertain the amount of profit attributable to the stolen money and pay half of it along with the original sum to its owner. A subtle method suffices for its return. Furthermore, he must repent to Allah for the theft and for delaying the return of the money.