When Weinberg freshman Whitney Gretz received two phone calls in January to confirm credit card charges for more than $800 worth of designer clothes, she thought the orders might be a birthday surprise from her mom.

But when Gretz called home, she discovered that her mom had never heard of the online clothing company. Gretz’s real birthday surprise? Someone else was using her Discover Card account.

“It wasn’t because I lost my card,” she said. “It was just (someone using) my number. That’s what was so scary.”

Gretz is one of an estimated 500,000 to 700,000 victims of identity theft in the United States each year, according to FBI reports. The FBI cites identity theft — the misuse of a credit card number, bank account number or Social Security number — as the fastest growing white-collar crime in the United States. A 2003 survey by the Federal Trade Commission suggested the problem is even worse, estimating that 10 million Americans were affected by identity theft that year.

And it can take years for victims of identity theft to repair their credit records, national experts and local police said.

Although everyone should be careful about protecting personal information, college students should take extra caution, said Jordana Beebe, communications director for the California-based Privacy Rights Clearinghouse.

“When you’re talking about your average college student, you’re talking about someone who doesn’t really have a lot of experience with the credit industry,” Beebe said.

Beebe said criminals target credit-confused college students in a number of ways, including lifting information from pre-approved credit card offers or other personal documents. But college-age victims are not alone.

“Identity theft applies to everybody — not just college students,” said Deputy Chief Michael Perry of Evanston Police Department. “It can happen anywhere. You have to be careful where you leave your credit card. You have to be careful who you show your credit card to.”

But for one Evanston resident, being careful was not enough. Two years ago, someone who stole credit information from a resident’s apartment mailbox eventually created more than 20 new accounts under the name of the 65-year-old Evanston man, who wished to remain anonymous so he is not victimized further.

“It has to be one of the most unsettling things,” he said. “Somebody has your identity and they can be using it however they want to. They can be doing all kinds of terrible things in your name.”

The average personal loss in cases where new accounts are opened is $10,200, according to the FTC survey. When an existing account is misused — as in Gretz’s case — the average loss is $2,100.

Beebe said she urges consumers to get a copy of their credit reports once a year and check them for suspicious charges. But identity theft is not always a matter of credit cards, she added. She said Social Security numbers are one of the most important personal identifiers to protect, especially for college students.

“So many colleges and universities tend to use Social Security numbers as a college ID number and that can make students more susceptible to identity theft,” Beebe said.

At Northwestern, many students use Social Security numbers for services such as meal plans and registration. University Registrar Suzanne Anderson said the university is working to eliminate systems that rely on Social Security numbers. She added she encourages students to use their seven-digit student ID numbers.

The U.S. Department of Education launched an identity-theft education Web site in December to address the fast-growing crime. Students can visit www.ed.gov/misused to learn what to do if victimized.

Department of Education spokesman Jim Bradshaw said the first step victims of identity theft should take is to contact the fraud departments of each of the three major credit bureaus: Equifax, Experian and TransUnion. Victims should then close the accounts that have been tampered with and file a police report.

Although Gretz — who immediately canceled her account — has never confirmed how her card number was stolen, following these steps quickly paid off for the man in Evanston. He said the perpetrator later was arrested in south Evanston with about 10 credit cards under different names.

Under the 1998 Identity Theft and Assumption Deterrence Act, identity theft is a felony with a penalty of up to 15 years in prison and a fine of up to $250,000. But a conviction will not clear a tarnished credit history, warned EPD’s Perry.

“Our job is to locate the offender, but it’s your responsibility to clear your own credit record up,” he said. “It’s a messy job.”