By Jim Donovan

PHILADELPHIA (CBS) — The Internal Revenue Service is launching a criminal investigation after revealing that information on more than 100,000 tax payers was accessed by thieves online. 

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The I.R.S. says that between February and mid-May thieves from possibly Russia accessed a system called Get Transcript.  It’s an I.R.S. site where taxpayers can get copies of their old tax returns.  Once the crooks got hold of the information they were able to file new returns and collect nearly $50 million dollars.

The I.R.S. says information stolen from the Get Transcript site was used to claim the tax refunds of 15,000 people before they detected the breach.  About 200,000 attempts were made to steal information, and a little more than half of them were successful after security filters failed to stop them.

“They needed a Social Security number and a verifiable email address, one that was attached to the Social Security number and then they get a series of authentication questions and if they can answer those they’re in,” says identity theft expert and co-founder of Credit.com, Adam Levin.

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The breeched system has since been disabled, and the I.R.S. says it’s main computer system which handles tax filings remains secure.  But Levin believes that victims will be dealing with this for years to come.  He says, “If you’re a victim of tax related fraud, you’ve got to assume because they have the information they need to do that fraud, that they will be in a position to commit all kinds of other kinds of fraud as a result of the access to your information.”

The I.R.S. says it is notifying taxpayers whose information was accessed and will offer them credit monitoring.  If you learn that you’re one of the victims, you should request that they give you a personal identification number (PIN).  It will provide you with another level of security from here on out.  You’ll need to submit this PIN along with your Social Security number when filing your returns in the future.

For more information visit:

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http://www.irs.gov/Individuals/Get-An-Identity-Protection-PIN