IRS Officials Blame Russian Cyber Criminals for Massive Data Theft From Tax Return Website

If you're one of the tens of thousands of Americans whose personal tax information was stolen from the Internal Revenue Service's (IRS) website, you could have Russian cyber criminals to blame, according to new revelations from officials at the federal tax agency.

This week, the IRS revealed a mass data theft carried out by hackers who stole the personal details from some 100,000 American tax payers in an elaborate scheme by an organized criminal outfit to try and claim fraudulent tax returns. Two unnamed IRS officials familiar with an ongoing criminal investigation into the alleged breach reportedly told the Associated Press Thursday that the agency believes the hackers are Russian, based on computer data indicating who accessed the information in question.

The thieves had reportedly been siphoning a trove of private information about taxpayers from an IRS tax return website called "Get Transcript" since February. That information included Social Security numbers, tax filing statuses, street addresses, and birth dates.

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The hackers used the stolen information to fraudulently claim up to $50 million in tax refunds, IRS Commissioner John Koskinen told reporters at a press conference Wednesday. IRS technicians discovered the breach roughly two weeks ago and the site has since been shut down.

"We're confident that these are not amateurs," Koskinen said. "These actually are organized crime syndicates that not only we but everybody in the financial industry are dealing with."

Koskinen added that the hackers have not only targeted IRS databases, but also others in the financial sector. He did not say where the hack had originated at the press conference.

In addition to an internal IRS investigation, the inspector general has also launched an inquiry into the incident. The agency said it is also planning to notify every tax payer caught up in the hack and will provide them with credit monitoring services.

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The Associated Press contributed to this report.