You may be able to reach out to the service provider for assistance as well. They may be able to set up a trap and trace device on the line in question, though I'm not sure if this would catch/trace SMS messages. They might set one up for you due to there being credible threats. (Note you will need court orders within a couple days to keep the trap & trace active)
Though I agree with others, the local LEO's need to be involved as well, or at least a discussion with them to find out why they are not willing to help.
LOL not meant to embarrass anyone, it was a question, and fair one at that. If you go to the police and they can't help, how can hiring someone outside of the Law help, unless they are counsel with the ability to have a pipeline to the DA or USA.
You keep being the spelling police, I'll keep being good at computer forensics and investigations.
What's with the MacGuyver comment? Do you have some sort of deep-seated complex?
Armresl for being a TV show from your generation, I'm surprised you don't know how to spell the TV character you are trying too use to embarrass other people.
It is "MacGyver"
not MacGuyver
… If you go to the police and they can't help, how can hiring someone outside of the Law help[?]…
Are you being deliberately obtuse? If you can't conceive of an answer to your question then I'd suggest reassessing your investigative skills.