The Internal Revenue Service on Thursday announced the results of a national sweep that targeted identity theft suspects in 32 states and Puerto Rico, and which involved 215 cities and surrounding areas, including Cincinnati.

The aggressive enforcement effort against nearly 400 identity theft suspects led to more than 730 enforcement actions in January, said Steven T. Miller, IRS acting commissioner, in a call with reporters.

“With the tax filing season now under way, we want to be clear that there is a heavy price to pay for committing refund fraud and identity theft,” Miller said.

The IRS opened about 900 criminal investigations into identity theft issues in fiscal year 2012, which was triple the number from 2011, Miller said. In the first four months of the current fiscal year, the agency has opened more than 560 criminal investigations, he said.

Total enforcement efforts against identity thieves are also increasing. In fiscal year 2012, there were 2,400 enforcement actions against 1,310 suspects. The agency’s enforcement actions for the current fiscal year total 1,703 against 907 suspects.

The effort that intensified in January involved 734 enforcement actions related to identity theft and refund fraud. The effort led to actions involving 389 people nationwide, including 109 arrests, 198 indictments, informations and complaints, and 47 search warrants, officials said.

IRS special agents in 2012 spent more than 500,000 hours on the issue, more than double in 2011.

“These numbers show that the IRS is very serious about pursuing identity thieves and protecting the taxpaying public,” Miller said.

The IRS also has improved its efforts to block fraudulent refund claims before they are processed. “In fiscal 2012 we prevented the issuance of more than $20 billion in refunds that were fraudulent, up from $14 billion the year before,” he said.

A federal grand jury in Cincinnati last month indicted four people in a scheme to file false claims for federal income tax refunds with the IRS totalling at least $654,550, according to officials from the IRS Cincinnati Field Office. Another person involved in the scheme agreed to plead guilty.

Charges of conspiracy to file false claims for federal income tax refunds with the IRS were filed against Ellis Maurice Scott, Bridgette Jones, Latasha Hampton, Marnay Love and Dione Howard, all of Cincinnati. Scott and Jones also face additional charges, including wire fraud and aggravated identity theft.

Officials said Scott and Jones allegedly possessed 15 or more unauthorized “access devices,” such as the names, Social Security numbers, and dates of birth of individuals, to prepare and file false income tax returns claim refunds. Howard allegedly purchased the means of identification from Scott for the purpose of filing false federal income tax returns, officials said.

Conspiracy to file false claims for federal income tax refunds with the IRS, and the possession of 15 or more unauthorized access devices are both punishable by up to 10 years in prison and a $250,000 fine. Wire fraud is punishable by up to 20 years in prison and a $250,000 fine.

Miller said there were 80 sentencings for identity thieves in fiscal year 2011, which increased to 223 in fiscal year 2012.

Convicted identity thieves are spending an average of four years in custody, Miller said. Some sentences in the current fiscal year have been more than 20 years, he said.