Groom Who Left Belongings in the Yeshiva

I study in an important yeshiva in Jerusalem, which, thank God, has many students and consequently many grooms. I would like to ask: A groom who got married and left the yeshiva, leaving behind belongings such as a fan and the like. Another student came and claimed it as ownerless property. A. Can the student take the item? B. Can the groom give it to another student after the second one approached him and reminded him that he forgot the fan in the yeshiva, or has he already lost ownership in favor of the first one who took it? Also, if possible, please provide the reasoning and source.

Hello and blessings 

If it is clear that the groom abandoned the item, the student who took it becomes the owner, and later the groom's statement to give it to another would not be effective. However, usually, the groom does not abandon his belongings but forgets them, and then there is the mitzvah of returning lost property to inform him of the loss. In such a case, the first one who took it did nothing, and the item belongs to the second, who received the owner's permission to take it.