(CNSNews.com) - Kevin O’Reilly, a member of the White House National Security Staff who  regularly communicated about Operation Fast and Furious with the Arizona-based  ATF agent responsible for running the operation that allowed guns to flow to  Mexican drug cartels, was suddenly transferred out of the White House and into  Iraq in July 2011.

The transfer took place shortly after the ATF agent had testified in the House Oversight and Government Reform Committee and the White House had provided the committee with  a series of emails that O’Reilly and the agent had exchanged while Fast and  Furious was underway.

Since then, the White House has declined to allow O’Reilly to be interviewed  either by the committee or by Justice Department Inspector General Michael  Horowitz, who conducted the administration’s internal investigation of Fast and  Furious. The White House also refused to give the inspector general access to  internal White House communications relating to Fast and Furious.

Under Fast and Furious, the ATF and the Justice Department deliberately  allowed known straw purchasers for Mexican drug cartels to buy about 2,000 guns  at U.S. gun stores. In December 2010, two of these guns were found at the scene  of the murder of Border Patrol Agent Brian Terry. Many more of the guns were  found at crime scenes in Mexico.

In Sept. 20 testimony before the Oversight Committee, Horowitz said that the  White House’s refusal to let O’Reilly speak and to provide the IG’s office with  access to relevant internal White House communications “made it impossible” to  “pursue that aspect of the case.”

In a letter they sent to O’Reilly’s attorney last Thursday, House Oversight  Chairman Darrell Issa and Sen. Charles Grassley, the ranking member of the  Senate Judiciary Committee, warned that Issa would subpoena O’Reilly if he did  not agree to testify.

“We have been trying to arrange to speak with your client, Kevin O’Reilly,  for nearly a year now,” Issa and Grassley wrote. “Earlier this year, you agreed  to make O’Reilly available for an interview if the White House authorized his  participation. The White House, where O’Reilly worked during the pendency of  Operation Fast and Furious, refused to make him available, citing ‘an  insufficient basis to support the request.”

“If O’Reilly chooses to continue to make himself unavailable, Chairman Issa  will have no further alternative but to use compulsory process to require his  testimony before the committee,” they wrote.

In a March 28, 2012 letter to White House Counsel Kathryn Ruemmler, Issa and Grassley had said: "O'Reilly's personal lawyer has represented to the Committee that he would permit his client to speak to the Committee in the absence of any objection from the White House."

In an April 5, 2012 response to Issa and Grassley, Ruemmler wrote: "In light of the important Executive Branch confidentiality interests and institutional prerogatives implicated by your request, including those of NSS [National Security Staff], and in the absence of any evidence that suggests that Mr. O'Reilly had any involvement in 'Operation Fast and Furious' or was aware of the existence of any inappropriate investigative tactics, there is an insufficient basis to support the request to interview Mr. O'Reilly."

In their letter to O'Reilly's attorney on Thursday, Issa and Grassley said that without getting O’Reilly’s story it would be  impossible to determine the role that the White House played in Fast and Furious.

“By not interviewing O’Reilly, the OIG could not fully determine the role the  White House played in Fast and Furious,” Issa and Grassley wrote. “Given that  O’Reilly was the link connecting the White House to the scandal, and that the  President subsequently asserted executive privilege over documents pertaining to  Fast and Furious, it is imperative that the American people get to the bottom of  O’Reilly’s involvement in Fast and Furious.

“To do this,” Issa and Grassley said, “Congress must speak with O’Reilly  directly.”

The letter indicates that while O’Reilly was working at the White  House he communicated for more than half a year about Fast and Furious  with ATF Special Agent in Charge William Newell, who was in charge of the  operation for the ATF in Arizona.

“Last year, the Department of Justice and the White House produced several  series of email exchanges ranging from July 2010 to February 2011 between  O’Reilly and William Newell pertaining to Operation Fast and Furious and  Newell’s work as head of the ATF Phoenix Filed Division,” wrote Issa and  Grassley. “At that time, O’Reilly was serving on the National Security Staff at  the White House. Several of the emails produced by the Department and the White  House raise serious questions about the nature and the purpose of their  interactions. For example, one email from Newell, the Special Agent in Charge of  the ATF Phoenix Field Division, began, ‘You didn’t get these from me …’ Another  email shows Newell’s intent to circumvent his leadership structure in talking  with O’Reilly: ‘Just don’t want ATF HQ to find out, especially since this is  what they should be doing (briefing you)!’”

When Newell testified before Issa’s committee on July 26, 2011, he said of  White House aide O’Reilly: “He has been a friend of mine for a long time, and he  asked me for information.”

“Not that I shouldn’t have been talking to him,” Newell testified. “He is a  friend of mine. He asked for information and I provided it to him.”

In one of O'Reilly's emails to Newell that the White House did give to the  committee, O’Reilly told Newell he intended to inform two other White House  National Security staff members--Dan Restrepo, the senior director for Western  Hemisphere; and Greg Gatjanis, director for the Counterterrorism and  Counternarcotics--about the gun trafficking investigation.

On July 28, 2010, O’Reilly responded to Newell: “This is great; very  informative. OK to share with Sr. Director Dan Restrepo and CT/CN Director Greg  Gatjanis? Would not leave the NSS, I assure you.”

Newell replied: “Sure, just don’t want ATF HQ to find out since this is what  they should be doing (briefing you)!”

Issa and Grassley learned that shortly after Newell’s July 26 2011 testimony,  O’Reilly was transferred from the White House to Iraq.

“Additionally, we recently learned that, last July, O’Reilly was suddenly  transferred out of the country to serve in Baghdad as the head of the Police  Development Program, a multi-year, multi-billion dollar program designed to  train Iraqi security forces,” Issa and Grassley wrote.

“O’Reilly’s sudden transfer to Baghdad occurred just days after the  aforementioned e-mails with William Newell were produced to the Committee and  Newell testified about them before Congress,” Issa and Grassley wrote.  “Additionally, we have learned that O’Reilly took the place of a previously  selected individual—and individual who had gone through a competitive  application process and thorough vetting process, had the necessary  qualifications, and whose spouse was already in Baghdad in anticipation of the  individual’s arrival—to serve as the head of the Police Development  Program.”

A State Department official told CNSNews.com last week that O’Reilly was no  longer assigned to Iraq and is now between assignments—but would not say what O'Reilly's next assignment is.

“I can confirm that he [Kevin O’Reilly] is no longer in Iraq but he has not  yet started in his next position,” said a State Department official. “So, I  can’t confirm what that position is. I just don’t have any information on that  right now, what his next position will be or when he will be starting.”

The State Department official said there is no official biography for  O’Reilly because he is not in a senior level post. However, public records do  not indicate that O’Reilly had experience in the Middle East before his sudden  posting to Iraq.

O’Reilly’s  LinkedIn profile says he started working for the State Department as a  foreign service officer in 1987 and that he started at the Obama White House in  May 2009.

Before going to the Obama White House, he had worked from September 2008 to  May 2009 for the State Department’s Office of the Coordinator of  Counterterrorism, and from May 2006 to August 2007 as the director of Latin  American Affairs for the Department of Homeland Security.

O’Reilly worked from 2005 to 2006 for the office of Sen. Dick Durbin (D-Ill.)  from 2005 to 2006 as a Pearson Fellow.

O’Reilly was the deputy political counselor for the U.S. Embassy in Mexico from 2003  to 2005, officer in charge of Columbian Affairs from 2002 to 2003. He was the  executive assistant to the assistant secretary for Western Hemisphere Affairs  from 2001 to 2002. He served as the officer in charge of Iberian Affairs for  NATO Division J-5 from 2000 to 2001. He served as the political affairs officer  for the U.S. embassy in Santo Domingo, Dominican Republic from 1997 to 2000;  worked as the political affairs officers for the U.S. embassy in Buenos Aires  from 1994 to 1996; and was the executive secretariat for the State Department in  1993.

O’Reilly apparently was willing to talk to congressional investigators over  the phone while he was working in Iraq, according to a March 28, 2012 letter  from Rep. Darrell Issa (R-Calif.), the chairman of the House oversight  committee, and Sen. Charles Grassley (R-Iowa), the ranking member of the Senate  Judiciary Committee. White House counsel Kathryn Ruemmler responded in an April  5, 2012 letter that “there is an insufficient basis to support the request to  interview Mr. O’Reilly.”

During the House Oversight and Government Reform Committee hearing on Sept.  20, Issa asked Justice Department Inspector General Michael Horowitz, “Can you  tell us a little bit about your efforts to try to interview Kevin O'Reilly, a  member of the national security team?”

Horowitz responded, “We reached out to his lawyer, requested an interview. We  have no basis to compel interviews from individuals who are outside the  Department of Justice. He does not work in the Department of Justice. So we had  to ask for a voluntary interview, and he denied our -- his lawyer told us he  would not appear voluntarily.”

Issa responded, “Would it surprise you that he’s been in Afghanistan and  we’ve been denied even the ability to serve a subpoena on him?”

Horowitz responded, “I was not aware of where he was, but I was told by his  lawyers,” Issa corrected himself, “I'm sorry. Iraq. Sorry.”

Horowitz said, “As I said, we weren’t -- I don't recall knowing myself where  he was, but we were told by his counsel he would not appear voluntarily.”

Later in that same hearing, Rep. Blake Farenthold (R-Texas) asked Horowitz,  “You noted also in your report that the White House refused to share internal  communications with you during your investigation of Fast and Furious. We've  noted a connection into the White House through Kevin O'Reilly at the National  Security Council. Do you believe the White House’s refusal to share these  documents limited the scope of your investigation? And would this committee be  well served by pursuing an investigation in that avenue?”

Horowitz answered, “Well, as we noted in the report, and as you know,  congressman, we did not get internal communications from the White House and Mr.  O’Reilly’s unwillingness to speak to us made it impossible for us to pursue that  angle of the case and the question that had been raised.”

Farenthold followed, “So it would probably be worthwhile for us to pursue.”  Horowitz said, “Well, certainly we have sought to pursue every lead we could. So  I can just tell you, from our standpoint, it was a lead we wanted to  follow.”

In their letter to O’Reilly lawyer, Issa and Grassley note that the program  in Baghdad that O’Reilly was assigned to run was cited in an inspector general’s  report for wasting tax dollars.

“The program ‘drawn up to be the single largest State Department program in  the world,’ recently came under fire in a report by the Special Inspector  General for Iraq Reconstruction, published a year after O’Reilly took the helm,  for having a ‘total amount of de facto waste … to about $206 million.’”

“These events raise serious questions about O’Reilly’s assignment in Baghdad,  the motivation for his transfer there, his qualifications for his position  there, and the potentially extreme waste of taxpayer dollars in placing O’Reilly  in this position,” Issa and Grassley wrote