price after being mixed with his own moneys is not its equivalent; and although he is the richer by the transaction, yet it cannot be said that he is the richer unjustly, and so he is not bound to restitution. [1]
It is a disputed point among theologians whether a purchaser in good faith from a thief of stolen goods, on finding out that the goods were stolen, may return them to the seller if he cannot otherwise get back his money. It would seem that in conscience he may do so, for in so doing he does not wrong the rightful owner; he replaces the goods where he found them, so to say, and they are in no worse a position through having been for a time in his possession. He is justified in leaving them there if he cannot otherwise save himself from loss. [2] Such an action, however, might bring him into collision with the law of the country. In England it might amount to misprision of felony or be considered compounding a felony.
SECTION II
Possession of Another's Property in Bad Faith
1. When one has wrongfully had possession of another's property, well knowing that he had no right to keep it, on coming to a better frame of mind he is bound in the first place to restore the property itself to its rightful owner. Moreover, if the owner has suffered any special loss through being deprived of what belongs to him, the thief must make this good, inasmuch as he was the unjust cause of it. Furthermore, all natural or civil fruits of the property he must restore to the owner, for res fructificat domino; and if they have been consumed, their value must be given to him or else he will not have his own. Any fruits which are due to the industry of the thief, and all necessary and useful expenses which he incurred in respect of the property, he may in conscience deduct from what must be restored to the owner, for justice only prescribes that each one should have his own, not more than his own.
2. If another's property is saved from fire, or from certain destruction in any other way, it still belongs to the former owner, for res clamat domino. At most, he who saved it has a claim to reasonable compensation for his trouble. If stolen goods perish in the hands of the thief, he must make restitution for them to the owner, unless they would have perished in the