A few hours after NBA star Kobe Bryant had sex with an hotel worker last summer, the woman exchanged sms with two other people and accused him of rape. Those messages could help determine whether the sex was consensual or not.

Text messages are increasingly used as evidence in court. In Oregon, they played a role to convict a man who had killed his wife and sent her e-mail and text messages to terrorize her. In Georgia, a 17-year-old boy was arrested for investigation of solicitation of sodomy after a 12-year-old girl’s parents complained of sexually explicit messages she had received.

In Europe and Asia, SMS have played a prominent part in some criminal cases.

In Sweden, SMS contributed to prove that a nanny influenced by a pastor of a religious sect murdered his wife and a neighbour with whom she was alleged to be having an affair. And police in Japan are examining e-mail and text messages to determine whether a 12-year-old girl was killed by a classmate.

While some European countries require telecoms to store text-messaging content and other communications for law enforcement purposes no such requirement exists in the United States.

The woman’s mobile phone company, AT&T Wireless states that messages not immediately delivered are held for 72 hours for more delivery attempts — then deleted. How messages in the Bryant case would be available four months later isn’t known; they were probably retrieved from an archival storage system.

Apparently, information about text messages — including the sender, recipient and location of sender — is kept for billing purposes. The software used to store that information also can store content.

“I think in these days of corporate fraud and in these days of terrorism we’re seeing more and more reason to store forever,” said Jeff Kagan, an independent telecommunications analyst. “Don’t ever say anything on e-mail or text messaging that you don’t want to come back and bite you.”

Details in CNN.
Related entry: Text security.