Halocho #929 - Finder's keepers?

If you find Jewish property that is obviously lost, you have an obligation to return it to it's owner.

However, if the object was "put down" and not dropped, then you are not allowed to move it; if you move it you are preventing the owner from finding it.

When in doubt, leave it alone, unless you know who the owner is and you will return it to them immediately.

Similarly, if you can prevent somebody else's property from being destroyed, damaged or stolen, you have an obligation to do so.

Source: Kitzur Shulchan Aruch 187:1, 3

- Danny
Monday, 24 Marcheshvan 5772