In highschool I had a gameboy color in my backpack with pokemon tcg in it.

I went to the bathroom and came back. It was no longer in my backpack after that. Thanks sophomore year physics class.

Other than law-enforcement, no one can find the customer details associated with an IP address.

Yeah, what you need is to subpoena the address to find out who the owner is of the internet connection. From there you can probably find out which construction worker lives there and take it to small claims court.

Probably not worth it