How do you track down prank calls that have no number?

Question

how do you track down prank calls that have no number?

without going to the police

Answer 1

There are two ways of doing this first when the call ionn your caller ID after they hang up, on your phone hit *69, secondly call your phone company that you have a prank caller, they can put a trace program on your phone.

Answer 2

dial *67