Think hitting that delete option on a text message kills it forever?

Think again.

That thought-to-be-erased information is often stored in the handset, sometimes for years to come, and is proving to be an increasingly valuable tool for law enforcement officers.

"It's anything from missing persons to harassment to pedophiles," said Pam King, chief of training for Pennsylvania-based BKForensics, a company that teaches law enforcement officers to retrieve cellphone data.

"Pretty much every crime you could imagine, cellphones could have some relevance as far as evidence goes."

Law enforcement officers from drug task forces across Alabama last week got the hardware and software needed and learned how to retrieve deleted text messages, photos and videos to help them in criminal investigations.

Billy Duckett, director at the law enforcement academy at Jacksonville State University, said the class, held at the Shelby County Sheriff's Office training center, is funded through a federal grant aimed at fighting the growing problem of methamphetamines.

"If they seize cellphones, there's an unlimited amount of data they can gain and use in the fight against meth," Duckett said.

But the knowledge they are getting goes beyond drug investigations.

Authorities recently arrested a man who was using his cellphone to communicate with a teen girl. Information retrieved from his cellphone provided enough evidence to charge him with the rapes of two girls, ages 10 and 14, in other states, said Russell Yawn, chief investigator of technology crimes with the Alabama District Attorneys Association.

Also recently, authorities nabbed a state college student who was making counterfeit driver's licenses and doing all of his business via his iPhone, Yawn said.

"We recovered e-mails, text messages, photographs and even a spread of the counterfeit licenses," he said. "He probably never envisioned anyone would be able to uncover this information."

King said since there is no standard cellphone, each device is unique and authorities have to figure out how to extract the data. They are trying to crack and hack as many types as they can.

As they do, cellphones are becoming more of a help than a hindrance to investigators.

"Obviously, if you know you have something incriminating on a phone, or any device, and you know you're a target of law enforcement, the first thing you're going to do is delete that information," she said. "Now that we're learning how to get to that deleted information, it's getting a little better."