Any process available to track/trace an incoming call on on a cell phone that shows up on the receiving cell phone as PRIVIATE or UNKNOWN? By trace/track I am asking if the caller himself/herself can be identified. This question is related to threatening phone calls.

How could I trace private phone calls at my home phone?

How can a trace private calls for free or can tmobile give ne da number by a charge at least

Someone called me from a pravate number, I am not sure weather it was the cell phone or landline, I would like to know how to trace it, because I didn't hear exatly what she was saying.

How do I find out who keeps calling me private on a landline phone number