

That sound really a hard to do.
Basically you have to formulate the right responses that this device is looking for when it is communicating over the Internet.
My only idea is maybe you can capture the device’s request and response using Wireshark and then use a dummy server to fire the same response s back to the device inside your vlan l. You’d also need to set a DNS to reroute the traffic properly. If the device is using encryption layers that’s basically impossible iirc.
Basically you are looking to set up your own very basic mitm for that device.







My first thought is contact police because only they have the resources to start an investigation, looking into phone data and thoroughly searching.
My second thought is if you know someone with knowledge or if you have time to read up on OSINT skills, these could help if you need to do your own search.
Maybe someone has better ideas though.