Rep. Tom Cole (R-Okla.) is having a rough 2008 cycle.

Since being elected as chairman of the National Republican Congressional Committee (NRCC) nearly 15 months ago, Cole struggled to get the campaign committee out of debt, clashed with House Minority Leader John Boehner (R-Ohio) and attracted criticism for seeking a seat on the coveted appropriations panel.

But Cole’s tenure got even rockier late last week with the revelation of financial irregularities at the NRCC and the subsequent notification of federal investigators.

The unusual development capped a week where five House Republicans announced they were not seeking reelection, raising the total this cycle to 28.

“The last week has been difficult,” Cole told The Washington Post.

Many details of the audit incident are still unclear. Cole issued a release on Friday stating that an unnamed former NRCC employee who served as an outside vendor had been terminated.

Cole said, “As part of our ongoing efforts to institute and strengthen financial controls at the [NRCC], we learned earlier this week of irregularities in our financial audit process. Since these irregularities may include fraud, we have notified the appropriate law enforcement authorities.”

Rep. Mike Conaway (R-Texas), who serves as the chairman of the NRCC audit committee, said he is confident that the NRCC had taken the necessary steps toward have the situation “fully investigated and fully resolved.”

Sources with knowledge of the situation said the Federal Bureau of Investigation and the Federal Election Commission have been notified.

Other than Cole and Conaway’s statements, the NRCC on Friday refused to elaborate or answer questions as its Capitol Hill offices were on a virtual lockdown.

“NRCC is buttoned up tight,” a GOP insider said Friday.

Some senior staff and Republican members of Congress were unaware of the situation until the NRCC issued it Friday release. As news spread Friday afternoon, rumors circulated about who was the focus of the probe.

It has been a trying time for Cole since he beat Reps. Pete Sessions (R-Texas) and Phil English (R-Pa.) for the NRCC post.

Cole has moved the NRCC back in the black after inheriting a debt of $16 million, but it took longer than he anticipated. In January of 2007, he predicted the debt would be gone by summer but the NRCC did not have more cash than debt until days before Christmas.

Meanwhile, the Democratic Congressional Campaign Committee has built a significant fundraising lead over the NRCC. DCCC has $35.1 million cash on hand and NRCC has $5.5 million cash on hand.

The cash disadvantage last year led to grumblings within the House GOP Conference and triggered Boehner to press for NRCC staffing changes –- a move that Cole soundly rejected.

When contacted on Friday, Boehner’s office directed questions back to the NRCC.

Cole did help Republicans retain seats in Ohio and Virginia following the deaths of two members in 2007. Yet, those victories have been eclipsed by the slew of Republicans who have announced they will not be seeking reelection. About a dozen of the 28 retirements are in competitive districts, with 10 of them being deemed tossups by the nonpartisan Cook Political Report

It remains to be seen whether the political ramifications of the federal probe at NRCC will be far-reaching.

In 2006, the Democratic Senatorial Campaign Committee quickly condemned the actions of a staffer who used a DSCC credit card to illegally purchase the credit report of then-Republican candidate Michael Steele (Md.). Shortly thereafter, the controversy faded.

Cole’s current bid for an open seat on the House Appropriations Committee has also drawn criticism from some GOP members and aides, who say the seat should go to a politically vulnerable lawmaker.

Cole has indicated he would use the appropriations seat to help raise funds for the cash-strapped NRCC.

With the election nine months away and political analysts predicting that House Democrats will pick up seats this fall, Cole will have to work even harder to restore what he described last month as the largest challenge facing his committee: morale.

“The expectations game is not one I worry about a great deal,” Cole said in a recent 90-minute interview with The Hill. “My biggest problem is not money or candidates, it’s Republican morale.

“There is no reason to be this down. I’ve been in this building when we were a hell of a lot weaker than this.”

Cole previously worked at the NRCC and the Republican National Committee as a top aide.