I have a victim who is being harassed continually by what I would call a stalker (ex-boyfriend). She gets mostly text messages now, all from spoofed numbers. I have been told it is impossible to get the real phone number if we subpoena her records or his. This is probably being used from an online app, and not really from his cell phone. Any direction to try in this realm is greatly appreciated. Have not had much experience in cell phone related issues.

Per Robert Malcolm:

Yes, it is possible to backtrack a SMS spoof (i.e. trace the message to determine who the actual sender of the message was). The first thing to know is that all SMS messages are delivered by a machine called an SMSC, and every SMSC requires a unique address; they need a Global Title which is similar to a telephone number and a Point Code which is similar to an IP address in SS7 terms.

In order to obtain these unique addresses a company is required to apply for them through a country regulator who will do background checks to ensure the company is legitimate. As a consequence every single SMS message sent can be traced back to the company that has been permitted to send a message by a regulator.

This company will then be able to trace the message down the value chain, and through its customers, and the customers of its customers and so on and eventually determine who the legal sending party was.

At this point it is very likely that the message was sent through what is called an SMS portal, which allows anyone to sign up and send a SMS after buying credits with a credit card and agreeing to simple terms and conditions. If a legitimate credit card was used, then you have found the guilty party, if a stolen credit card was used, then this becomes a little more difficult and using IP addresses and a variety of other digital forensic information could lead you to the guilty party.

99% of spoofed messages are sent via legitimate networks without trying to subvert the identity of the SMSC and as such the above is relatively easy to achieve in a few days after the message is sent. In rare circumstances a spoofed message could be sent in combination with another type of fraud; GT spoofing, which is a way of masking the identity of an SMSC. This is a very complex fraud, and is difficult but not impossible to trace, but requires the co-operations of a number of parties in the value chain and could take months to figure out.

If you are victim to a spoofed message, contact your carrier immediately and report it. They will run through the above procedure to ensure the offending party is blocked. In rare situations, where a crime is committed within the spoofed message e.g. death threat, then this should also be reported to local law enforcement who will investigate together with your carrier using the above process.