Bava Kamma 95B

גובה את הקרן מנכסים משועבדים, ואת השבח מנכסים בני חורין. דאתא בעל ארעא, ושקיל ארעיה ושבחיה.

he can collect the principal, i.e., what he paid for the field, from the robber’s liened property that has been sold. But he can collect the enhanced value, i.e., the value of the improvements made to the field, only from unsold property. Why are both of these collected from the robber? Because the owner of the field came and took both his land and its enhanced value.

מאי, לאו בעם הארץ ⁠– דלא ידע דקרקע נגזלת או אינה נגזלת, ואפילו הכי קאתי בעל קרקע ושקיל לארעא ושבחה, ושמע מינה: בשוגג נמי קניס? אמרי: לא; בלוקח תלמיד חכם, וידע.

The Talmud clarifies: What, is it not speaking of a purchaser who is an am ha'aretz, who does not know whether property can be stolen or cannot be stolen, and when he purchased stolen land from the robber, he did so unintentionally, since he was under the mistaken impression that this land belonged to the robber who sold it? And even so, the owner of the land can come and take the land and its enhanced value. And if so, one may learn from the baraita that R' Meir penalizes even one who acquires stolen items unintentionally. The rabbis say in response: No, it is speaking of a purchaser who is a Torah scholar, and he knew that the robber had no right to sell this land. The purchaser is therefore penalized and is required to return the enhanced value of the land as well.

תא שמע: לצבוע לו אדום וצבעו שחור, שחור וצבעו אדום ⁠– רבי מאיר אומר: נותן לו דמי צמרו. דמי צמרו ⁠– אין, דמי צמרו ושבחו ⁠– לא;

The Talmud again tries to determine the scope of the penalty: Come and hear what was taught in a Mishnah (100b): If one gave wool to a dyer to dye it red for him and he dyed it black, or to dye it black and he dyed it red, R' Meir says: The dyer gives the owner of the wool the value of his wool, since the dyer violated the owner’s instructions. It can be inferred from the Mishnah: The value of his wool, yes, he must give; but the value of his wool and its enhanced value, i.e., the amount by which the value of the wool increased because it was dyed, no, he is not required to give.