Why Identity Thieves Are Targeting Your Clients' (And Your) Tax Returns

State Returns Targetted

Even so, the federal agency has better fraud detection systems in place than most states, which likely explains why thieves are flooding some states with bogus returns, Litan said.

Ohio intercepted 58,000 fraudulent returns worth a combined $257 million in six months of 2014, a sharp rise from the 10,000 fraudulent returns asking for $8 million the year before, according to a Dayton Daily News investigation. The state is now sending about half of its electronic filers to an online quiz designed to verify identity.

Minnesota and Pennsylvania are among the states that have temporarily stopped processing returns because of suspected fraud.

Abandoning electronic filing in favor of paper forms is not the answer, said Ziegler, who is secretary and treasurer of the National Association of Enrolled Agents. Sending forms through the mail is not secure, and will not prevent you from becoming a victim when thieves have ready access to your private information from other sources.

Ziegler became a reluctant expert on identity theft after a babysitter stole her Social Security number and other private financial information to set up credit accounts in Ziegler's name. Since then, she has advised clients and others who have been the victims of tax refund fraud, including one of her enrolled agent colleagues.

Tax professionals have better access to IRS help than taxpayers, Ziegler said, as well as experience navigating its systems.

Once someone is a victim of tax return theft, the IRS issues them a personal identification number every year to help verify their identity, she said.

The only way to reduce the chances of refund theft is to "beat the criminal to the punch" by filing early, said Bob Sullivan, author of "Your Evil Twin: Behind the Identity Theft Epidemic."

"The other thing is to be aware it might happen," Sullivan said. "Any glitches in e-filing are a sign something could be wrong."