In a letter to President George W. Bush, Krongard said he was leaving "with a feeling of satisfaction and accomplishment at having promoted efficiency, accountability and positive change," The Washington Post reported. In an e-mail to State Department inspector general's office employees, Krongard defended some of his controversial decisions.

Krongard drew the ire of the House Committee on Oversight and Government Reform regarding his handling of key investigations.

Current and former department officials said Krongard impeded their investigation into allegations of contract fraud and mismanagement in the construction of the $736 million U.S. Embassy in Baghdad, as well as alleged arms smuggling by Blackwater Worldwide, under contract to protect U.S. diplomats in Iraq.

In an Oversight Committee hearing, Krongard denied impeding any investigation or taking action based on partisan politics.

He recused himself from the two investigations after the House committee confronted him with evidence of conflicts of interest, including his brother's role as a strategic adviser to Blackwater.