Caller ID is a service that allows people to see who's calling before they pick up the phone. Some callers have found a way to avoid revealing their ID by dialing *67 before they dial the number. If you've been receiving harassing or prank calls and want to find out who's behind the "private" ID, there are a few ways to go about it.
Sign up for a service called TrapCall (see Resources). After subscribing to TrapCall, you can choose to press the "Ingore" button when you receive an incoming call from a Private ID. The call will be rerouted to TrapCall's database, and then the revealed number will be sent to you.
Contact your service provider and ask about their policies regarding a service called "Call Trace." It allows you to dial *57 after receiving a harassing or prank call to trace the number. The number will be traced and recorded by the phone company.
Contact law enforcement. If you truly feel that your life, health or property are in danger, call your local police department. If the nature of the calls are threatening, law enforcement can put a trace on your cell phone and track down the person who has been harassing or threatening you.