The Arizona number wasn’t really disconnected; that was just an outgoing voicemail. The phone company will have a record of who owns it, but good luck getting that information.
“The phone company will have a record of who owns it, but good luck getting that information.”
Right. The phone company will only release the info in response to a subpoena from law enforcement or pursuant to civil litigation.
If you want, you can bring a John Doe action against the hacker and the voice mail number, and then serve a non-party subpoena against the internet service provider associated with the hacker’s IP address and the voice mail provider to get the info. Sometimes your local court clerk can be helpful in pointing you in the right direction to get all the filings together but it will cost perhaps a grand or two with the filings and to pay for someone to provide service of the non-party subpoenas particularly if they are out of state and are challenged. I’d recommend at this point just providing all the data you have to IC3, and hope for the best while keeping an eye out for the worst.