Some thoughts on users

However the requirements are expressed, whether in use cases or function points, it seems there are three types of basic users.

1) Someone who lost something
This user needs to report as much as they can about the object of interest, what it is, the location, shape, size, color, version, etc.

Curiously, when I've lost something, it's never one place I'm sure about. It could have been in multiple places. We'll need to deal with that twist.

Also, it would be a knockout if I had a photo of the thing or a link for a version of it.

This person may also want to leave contact information, although the confidential nature of it will need to be protected from casual access.

2) Someone who found something
This user needs to report as much as the can, too, about the object of interest: what it is, the location where it was found, the last location of it (e.g., did they leave it where it was, take it to the lost & found pickup office), etc. And once again having a photo would be dynamite, either of the actual thing or a version of it. And a photo here, too, would be awesome.

This person, too, may want to leave contact information which is protected from casual access.

3) Admins who need to maintain the system
In both of the above cases, these users won't need a login, although something to thwart bots (e.g., CAPTCHA) may be needed.

The admins need to add users who can maintain the system including functions to add other admin users, manage lost & found items, gather statistics, clean out the system, etc.

The admins could also set configuration parameters for the system (e.g., how much old stuff to show, how often to purge the system, etc.).

The admins jobs might also entail contacting the person who lost something. For instance, suppose someone finds a backpack and brings it to the lost & found office. An admin, recognizing that the backpack looks like one reported in the system, could initiate contact with the person looking for their stuff. The admin might simply have the system contact the person via email or text if something was brought to the office and the system notes that fact. If no acknowledgement comes back after say a week, the system might automatically move the item to the recycle bin to be emptied periodically.