This feels like an in-between that both wastes their time and adds you to extra lists.
Send the results somewhere! Not sure if "law enforcement" is applicable (as in, would be able/willing to act on the info) but if so, that's a great use of this data :)
I had a similar project a few years back that used OSX automations and Shortcuts and Python to send a message everyday to a friend. It required you to be signed in to iMessage on your MacBook.
Than was a send operation, the reading of replies is not something I implemented, but I know there is a file somewhere that holds a history of your recent iMessages. So you would have to parse it on file update and that should give you the read operation so you can have a conversation.
Very doable in a few hours unless something dramatic changed with how the messages apps works within the last few years.
MQTT is plug and play in Python. No more costly than a HTTP server.