This story was originally published at 1:43 p.m. and was updated at 4:25 p.m.

The Justice Department appointed a political supporter of President Obama who has donated to his re-election efforts to head its criminal investigation into the Internal Revenue Service's targeting of conservative groups seeking tax-exempt status.

House Oversight and Government Reform Committee Chairman Darrell Issa, R-Calif., and Rep. Jim Jordan, R-Ohio, a member of the panel, said Thursday they discovered that Barbara Bosserman, a DOJ trial attorney now spearheading the department's investigation of the IRS targeting, has donated at least $6,750 to Obama's election campaigns and the Democratic National Committee over the last several years.

Issa and Jordan wrote a letter to Attorney General Eric Holder, pointing out the conflict of interest and urging Bosserman's immediate removal from the ongoing IRS probe.

“By selecting a significant donor to President Obama to lead an investigation into the inappropriate targeting of conservative groups the department has created a startling conflict of interest,” they wrote.

“It is unbelievable that the Department would choose such an individual to examine the federal government's systematic targeting and harassment of organizations opposed to the President's policies," they continued. "At the very least, Ms. Bosserman's involvement is highly inappropriate and has compromised the Administration's investigation of the IRS."

A cursory search of Federal Election Commission records on the nonprofit Center for Responsive Politics' found a total of $4,250 donations to Obama or the DNC since 2008. The majority of those donations - $3,600 - went directly to Obama's presidential campaign with another $650 going to the DNC.

A Justice Department spokeswoman said federal law prohibits the consideration of political affiliation of career employees in making personnel decisions.

"Additionally, removing a career employee from an investigation or case due to political affiliation, as Chairmen Issa and Jordan have requested, could also violate the equal opportunity policy and the law," said Justice Department spokeswoman Dena Iverson.

A Justice Department official said the fact that Bosserman exercised constitutional rights to make a political contribution does not mean she is not acting professionally and in accordance with her oath of office and duties as a member of the bar. The official also said the department does not evaluate political contributions or affiliations of its career attorneys prior to making case assignments.

Issa's office later Thursday refuted Justice Department claims that federal law prevents them from considering a person's political leanings and activities when selecting an attorney to lead an investigation into a politically charged matter.

In fact, Issa spokeswoman Becca Watkins said Rule No. 1 in the department's ethics handbook states that “employees should avoid even the appearance of a conflict of interest.”

“The Department of Justice has the responsibility to ensure that there are no conflicts of interest between an attorney and the assignment,” she said.

Issa's committee has been investigating the IRS targeting of Tea Party and other conservative groups since early last summer. Last Spring news broke that the IRS had purposely delayed conservative groups' applications for tax-exempt status for months, and in some cases, years. In mid-May the Treasury inspector general for tax administration released a report that said the IRS asked inappropriate questions and targeted applications.

The same day the audit was released, Holder announced that the FBI would investigate the matter to determine whether any laws were broken in the targeting. A month after Holder's comments, however, then-FBI Director Robert Mueller, during a House Judiciary Committee hearing, said he couldn't say who was leading the investigation or how many agents had been assigned to the case.

In December, Issa and Jordan wrote new FBI Director James Comey complaining that the agency has yet to give the committee a briefing about the investigation into the IRS targeting and accusing the bureau and “possibly political appointees” within the Justice Department of “intentionally obstructing the committee's oversight efforts.”

“It was our hope that under your leadership, the Bureau would take this investigation seriously,” they wrote at the time.

Comey, who served as deputy attorney general during President George W. Bush's administration, became Obama's FBI director Sept. 4.