By Brian Todd, CNN
When investigating a crime, police can follow a trail of phone calls and e-mails, but text messages are much harder to track down.
Now, there's controversial, new push to persuade Congress to make it easier to see what you're typing and receiving on your cell phone.
Michelle Medoff says she started getting the harassing texts in early November. An anonymous person threatened to send nude photos of her to her mother, then to a wide circulation.
One text said, "I am so close to (expletive) sending them to every1. U are so sexy ull be an online star in no time unless u answer me."
The threats came from different cell phone numbers. Medoff, a model and a college student, was terrified.
"I was very very afraid. I mean, that week I didn't go to a night class because I didn't feel safe to walk by myself," she said.
It's those kinds of texts that U.S. law enforcement authorities want more power to investigate. Several law enforcement groups, including chiefs of police, sheriffs' associations are pushing Congress to pass a law saying your carrier has to record and store your text messages.
It's not clear how long they want them stored.
Scott Burns of the National District Attorneys' Association, one of the groups pushing for the new law, says his group favors a period of three or four months, may longer, if an investigation is urgent.
"If you're in the middle of an investigation and bad guys are communicating back and forth, whether it's a homicide, whether it's evidence of a crime, it's crucial. I mean 20 years ago we weren't talking about this. Today everybody has a cell phone, everybody texts and e-mails and is on social media. And that's where the evidence is today," said Burns.
Or not. As of 2010, major carriers like AT&T, Sprint, and T-Mobile didn't' retain any content of customers' text messages. They get rid of them immediately. Verizon keeps them only for up to five days.
Why can't law enforcement get the texts from individual cell phones? Burns says it's faster and more efficient to get it from the carriers, and he points out that of course, the bad guys often erase their incriminating texts.
But many believe the law enforcement benefit of mining texts doesn't outweigh privacy concerns.
Chris Calabrese of the ACLU says with some 60 billion text messages sent every day, there's just too much private information that would be stored.
"And that's not just something law enforcement can get. It's divorce attorneys, it's other investigators, It's the press. Even if you feel like you have nothing to hide, there's a lot of embarrassing and personal information there," said Calabrese.