IRS: 'Perseverance' led to increase in tax crime convictions

The agency investigated more than 400 more overall cases in fiscal 2012 than in fiscal 2011 and almost 300 more convictions during the same time period, while facing a nearly 8 percent staffing cut.

"The key to our successes is perseverance and dedication to working complex financial investigations aimed at stopping tax fraud, identity theft, offshore tax evasion, public corruption, money laundering and other financial crimes," said Richard Weber, the chief of IRS’ Criminal Investigation division, in a statement.

In addition to conviction rates reaching a three-year high of 93 percent, according to the IRS Criminal Investigation unit study released on Friday, jail time for tax-related crimes are also increasing – anywhere from 29 to 71 months, depending on the type of violation.

The report says the agency seized $754.7 worth of assets from criminal organizations, or bought with illegal funds, and collected $97.7 million in illicit proceeds during fiscal 2012.