The Interior Department's inspector general staunchly defended her integrity today as Republicans pelleted her with questions on her involvement in the agency's drafting of a report justifying a halt in deepwater drilling after the Gulf of Mexico oil spill.

Acting IG Mary Kendall has faced months of criticism over her office's investigation into a 2010 report that erroneously stated that a panel of scientists supported the moratorium. Republicans say Kendall's investigation -- which found no evidence of intentional wrongdoing -- was tainted because she attended meetings on the drafting of the report.

But today, Kendall did not sugarcoat her view on how the House Natural Resources Committee has pursued its case against her.

"For the past four months, I have weathered the scrutiny of this committee, which has used a unilateral approach to 'investigate' me by requesting select documents from the Office of Inspector General, drawing conclusions from those documents without all the facts, and presenting those conclusions to the public via press releases, challenging my integrity, independence and objectivity," she told the panel in her opening statement.

She later added: "The past 17 weeks have been the most painful and difficult of my entire career, not only because of the attacks on my personal integrity, but because this has eclipsed all the outstanding work that the OIG has done and continues to do."

The hearing was the latest in the panel's probe into whether officials purposely altered the 2010 report to buttress Interior Secretary Ken Salazar's drilling moratorium in the wake of the BP PLC oil spill. They say Kendall's investigation into the matter was skewed by her presence at meetings on the drafting of the report.

Kendall contends that she only attended information-gathering sessions, during which she neither intervened nor asked questions. She attended, she said, to learn more about deepwater drilling in preparation for her role on the Outer Continental Shelf Safety Board.

But Republicans argue that the IG report nevertheless did not delve deep enough. As evidence, they have pointed to emails from an IG case agent to a colleague, stating that he believes the editing of the 2010 report was intentionally done at the White House and that "we simply were not allowed to pursue the matter to the WH."

Today, Kendall unveiled another email from the same agent that appears to contradict that assertion.

In an email to Kendall over her edits on the IG report, the agent writes that whether the error was "intentional on the part of an overzealous White House staffer/editor, or simply an honest oversight, the jury will always remain out. The reader of the [IG report] will have to make their own speculations on that topic."

Today's hearing -- which was still ongoing as of publication time -- ranged across various issues that Republicans said compromised Kendall's impartiality, and it often became contentious.

At one point, Rep. Louie Gohmert (R-Texas) delivered a passionate speech on why the moratorium was a bigger disaster than the oil spill itself, and then shot questions at Kendall on how far her office pushed for emails between Interior and the White House regarding the report.

Committee Chairman Doc Hastings (R-Wash.) said Kendall's role on the OCS Safety Board, which reviewed offshore drilling safety issues, marked a step into the policy world that conflicted with her "primary function" of oversight.

"It's very difficult to understand how you cannot see how the dual roles are not in conflict," he said.

Kendall, for her part, argued that the board did not focus on policy.

Democrats characterized the hearing as a witch hunt on a trivial topic, arguing that the panel should instead be focusing on the safety of offshore drilling. Rep. Rush Holt (D-N.J.) said Republicans were merely upset that they couldn't find proof that the White House doctored the 2010 moratorium report.

"I don't see anything nefarious here," he said. "It's simply that the majority did not like the conclusions and they just want to discredit the report."