These are 2 very different things.
One would not lead to the other.
This thread i have shifted you post to, is where the paranoid schizophrenic posts get sent.
You sister may need help, either in the form of medical/ psychiatry OR the police, but not both.
If she believes she has a subdermal tracker that has be inserted and she is being tracked, this is simply not possible.
She may have been told this, but is just not true.
Depending on her mental state, she nay need to go to a doctor, and get an xRay, ANY sudermal implants wouod show up clearly
Check out this thread
Our implants are for many things, but tracking is not one of those things, because they simply can’t.
She may have be manipulated to think that she is being tracked, but the ex, would have to do it via other means. OSINT stalking, or even a gps device on her car etc. but there is certainly no way she has any technology under her skin allowing her ex to track her.
If you have time to read through this thread, you will see a common theme, among which, there are many claims, but NEVER any proof.
I hope this helps you in some way, If you have more questions, feel free to reply.
Good luck with everything