Explainer

Do Text Messages Live Forever?

How a dirty SMS can come back to haunt you.

Detroit Mayor Kwame Kilpatrick 

On Tuesday, a Michigan court released yet another batch of romantic text messages sent between Detroit Mayor Kwame Kilpatrick and his former chief of staff Christine Beatty in 2002 and 2003. In the messages, Kilpatrick and Beatty—who are charged with perjury for denying their affair in court—professed their love to one another and graphically described their sexual encounters. If you delete an old text message, can someone (or his lawyer) still find it?

Probably not—although there are exceptions. Most cell phone carriers don’t permanently save the enormous amount of text-message data that is sent between users every day. AT&T Wireless, for example, says it keeps sent text messages for 48 hours only—after that, they are wiped off the system. Sprint, on the other hand, keeps messages on its server for approximately two weeks. A court order could force a carrier to retain certain messages as part of an ongoing investigation, but it would probably be impossible to get the contents of a 2002 text message from most cell phone companies.

But as the Detroit Free Press noted after it uncovered the first trove of messages in January, Kilpatrick got in trouble because he used a government-issued SkyTel pager. SkyTel—which does much of its business through government and corporate contracts—offers message archiving as one of its key features. The mayor himself had reauthorized a directive noting that even deleted electronic communications sent and received by government employees would be stored automatically, although the memo did not explicitly mention text messages.

But even if your deleted text messages are off your carrier’s server, they may not be gone forever. When you press the delete button on your phone, the data that make up your message don’t disappear in an instant. Instead, the code is marked with a sort of tombstone that indicates which data can be overwritten. But until enough new information is added to fill that memory, your old text message will remain on your device. If you used a SIM card to store your text messages before you erased them, then there might be space for the remains of 30 or so deleted messages; if the messages are downloaded directly to your phone, several hundred deleted messages could stick around on your device. Eventually, of course, the deleted messages will disappear as memory is filled with new messages, photos, or videos. (See this Explainer for more on how to delete things permanently.)

Still, it isn’t always easy to recover a deleted message before it’s overwritten. First, you have to find a way to get the code off the cell phone. Then, you need to translate that code back into the human language of the original text message. If your messages are stored on a SIM card, you can purchase a device for as little as $150 that allows you to recover erased data on your own. But if your messages are stored directly on your phone, recovering deleted texts can be a long, technically challenging, and expensive process. While cell phone forensic specialists have emerged to help police and private investigators explore old phones, it could cost you several hundred dollars to ask them to find that text message you accidentally deleted.

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Explainer thanks Rick Ayers of the National Institute of Standards and Technology, Denise Howell, Gary Kessler of Champlain College, Rick Mislan of Purdue University, and Lee Reiber of Mobile Forensics, Inc.