Maybe now we know why Lois Lerner took the Fifth this summer. Rep. Darrell Issa, chair of the House Oversight Committee, demanded answers from now-IRS commissioner Daniel Werfel as to why IRS agents, including Lerner, transmitted confidential taxpayer data through personal e-mail accounts:

Senior Internal Revenue Service officials—including one at the heart of the IRS “targeting” scandal—violated agency policies and possibly federal records laws by using private email to send confidential taxpayer information, the GOP-led House Committee on Oversight and Government Reform said in a letter. In a Sept. 30 letter to IRS Acting Commissioner Daniel Werfel obtained by the Free Beacon, Oversight Chairman Darrel Issa (R., Calif.) said an investigation revealed a “troubling pattern” of at least four top IRS officials using their private email addresses to relay confidential tax information. “This not only raises the prospect of violations of the Federal Records Act but it also raises data security concerns and violates internal IRS policies,” Issa wrote to Werfel. The committee discovered the emails while investigating the ongoing IRS scandal that began earlier this year when an official admitted that the agency targeted conservative groups during the 2012 election. Lois Lerner, who headed the IRS’ tax-exempt division at the heart of the scandal, is one of the officials named in Issa’s letter.

Lerner is actually one of four IRS officials who sent such data over personal e-mail accounts, according to Issa’s letter. The others include Werfel’s predecessor Douglas Shulman, who stepped down last year, and a senior technical adviser in Lerner’s Exempt Organization Division, Judith Kendall. Kendall didn’t disclose that fact during the initial discovery period in Oversight’s probe, and Issa declares that to indicate the IRS’ general lack of cooperation in the probe:

“According to the IRS, you did not inform the IRS that you had such documents housed in your non-official email,” Issa wrote. “The discovery of these documents suggest that you were not forthcoming to the IRS about documents related the Committee’s investigation in your personal possession.” Issa said the committee’s findings suggest “such use is a systemic problem throughout the IRS.”

So far, the attitude of being above the law seems to be a continuing theme in this investigation.

As C.J. Ciaramella points out, these transmissions would violate both IRS regulations and federal law on their own. There is also the issue of obstructing Congress by not providing this data under the original subpoenas, which adds felony charges if Oversight decides to pursue them — and Issa isn’t likely to be terribly forgiving on that point. All of these would have to be prosecuted through the Department of Justice, however, and it’s far from clear that Eric Holder will cooperate with Congress on this probe. So far, no one’s heard much from the FBI since the early summer admission that they hadn’t even begun talking with witnesses on the scandal.

The other option is to get a special prosecutor for this case — and that’s increasingly becoming the least-bad choice.