CHICAGO (CBS) — Identity thieves go to great lengths to steal your identity. But all too often, scammers latch onto a relatively easy way to do it, using a loophole in the post office’s change-of-address system.

Donald and Debby Kroll found that out after they stopped getting expected mail. When they inquired about it at their post office, they learned their mail was being forwarded to an address in Florida.

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“I couldn’t figure out who in God’s name forwarded it?” said Debby Kroll.

For 2 weeks, the Kroll’s bank statements, credit card bills and tax documents were being delivered to a vacant home in Pembroke Pines, Florida.

“The post office is letting them steal your identity. It’s like giving a car thief your keys and saying here you go.”

Change-of-address forms are readily available at any post office. All you have to do is fill out the card and drop it in the nearest mailbox. Scammers can then collect your mail at a vacant home or fake address.

“I’ve had so many conversations with so many people at the post office. One person did say they realize it is a problem,”said Kathia Capellupo, who lives in Boston. Capellupo also had her mail forwarded by someone else to a different vacant apartment  — also in Pemboke Pines. A red flag.

“It suggests that you’ve got a nation-wide racket being conducted out of this area of Florida where they’re victimizing people across the country,” said fraud expert William Kresse.

Police say the crooks are usually long gone by the time victims complain.

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“Identity theft is a top priority for us. However, we can only do so much in an investigation based on what evidence is gathered,” Pembroke Pines Police Cmdr. Al Xiques said.

A 2008 Inspector General report warned that the “postal service should improve controls to ensure proper authorization and validation of COA request.”

While the Kroll’s say they never got a satisfactory answer to their complaints at the post office, security experts say more can be done to prevent this type of fraud.

For example, says Kresse, “Have the person go up to the window at the post office, hand in the form and show identification before that mail gets forwarded.”

Now the Kroll’s worry about what the scammers can do with the information they may have gleaned from their mail.

“You can never feel safe once you feel violated,” Debby noted.

Postal officials would not answer CBS 2’s questions about these cases or about starting a system to confirm identities before processing address changes. They say letters are sent to both the original and new addresses once a request has been submitted, so you will get some warning if someone else has forwarded your mail and you can take steps to cancel it at your post office. The Kroll’s say they never got that notification at their home, however.

The post office also says that change-of-address requests made online have one protection — you have to use a credit card to pay a fee. And, in effect, that can be a check on whether the actual homeowner is ordering the change.

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The postal service also says complaints like these are rare, but it continues to implement security enhancements.