If someone came to my house and had in their pocket $100. When they were in my house the money was lost. After a few moments I find a $100 on the floor of my house. Is it pashut that it belongs to me because of "chatzer koneh"? Even if the person will say that they had a $100 and now they don't, does it still belong to me? How far do we extend the klalim that when a person looses money he is normally misya'ash from it.
My kavana with the question is more of a tzrich iyun that I'm trying to understand. I thought pashut that it should belongs to the owner of the house. However this was difficult for me to believe that even though the guy is standing right there and claiming to have lost it that it wouldn't go to him.
Perhaps the chashuvah yungerleit from the Kollel can help in clarifying these dinim.
Yehoshua, Yerushalayim, Eretz Yisrael
1. The fact that we know who lost the money does not really change anything, since we assume that he has been Meya'esh.
2. In this instance, however, I believe you would not be able to keep the money due to the fact that your Chatzer is Koneh the money as soon as he lost it, which would be even before he has a chance to be Meya'esh. We assume that he notices immediately and is then Meya'esh, but this must still take a few seconds at least by which time your Chatzer has been Koneh the money. Accordingly, it is considered a situation of "b'Isurah Asah l'Yadei," and you are Chayav to do Hashavas Aveidah.
3. Furthermore, the Poskim say that in certain circumstances the Aveidah should be returned Lifnim mi'Shuras ha'Din. According to the Shulchan Aruch ha'Rav (CM Metzi'ah u'Pikadon 18), this includes a case of Yi'ush and would therefore apply in your case even if the Yi'ush happens before it came to the possession of the finder.