Bava Metzia 15 - Repossession of a Stolen Field
If one sells a field to his fellow and it is discovered that the field was not his to sell - that the seller had stolen the field - and the rightful owner repossesses the field, the defrauded seller has the right to compensation for his money by suing the seller.
However he has no right for the value of the improvement to the land, such as a crop or a house. Since the field was never his, the purchase money is considered a loan. The payment for improvement looks like interest which is forbidden - says Shmuel. The accepted ruling is that the purchaser has the right to improvements.
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