Before an officer can begin an investigation, you must successfully trace at least two of those calls and document the trace. Information about how to do this is printed in your telephone book or call your telephone company for help. After the traces, you must call the telephone company as well before you can report it to the police. When you do call the police department, obtain a case number that can be furnished to the telephone company.
Caller ID is not the same thing as tracing a call. If you have a caller ID box, you still must work with the telephone company to trace the call. Caller ID is not admissible in court.