Telephone harassment occurs when someone intends to annoy, harass or threaten you by:
- making a telephone continually ring
- making lewd, indecent, or obscene comments, suggestions or requests
- a telephone call where the caller does not identify himself
- repeated telephone calls where the conversation consists only of harassment
- a telephone call with intent to intimidate using heavy breathing or silence
Being harassed or threatened, you are totally justified in using reverse phone lookup to find out who the caller is. Get the name and address of the owner of that phone number. Once you have this information you can take the next step on your end which may involve calling authorities so they can get to the bottom of the issue.
Do not take the law into your own hands and "track down" the person who is threatening you over the phone. Let the authorities handle that.