Mr. Ward had been treasurer of the national Republican committee since 2003. He had also been a partner in a private campaign consulting firm, Political Compliance Services, that gained notice in the 2004 presidential campaign because of its work on behalf of Swift Boat Veterans for Truth, a group that ran advertisements that criticized the military record of Senator John Kerry of Massachusetts, the Democratic presidential nominee.

Committee officials said that bookkeeping irregularities were discovered in January after the chairman of the panel’s auditing committee, Representative Mike Conaway of Texas, a certified public accountant, repeatedly asked to meet with representatives of the audit firm that was supposed to be reviewing the committee’s books.

“I just kept insisting that we meet with the auditors,” Mr. Conaway said in an interview. “It finally came into my head, and as the circumstances unfolded, that no audit had been done.”

He said that Mr. Ward had promised to set up a meeting with the auditors and scheduled the gathering in late January.

But 30 minutes before the scheduled meeting, committee officials said, Mr. Ward sent an e-mail message to colleagues announcing that, in fact, no audit had been done. The officials said the fund-raising committee had since determined that its books had not been audited since 2003 and that Mr. Ward had submitted a series of falsified audits. The committee then called in the F.B.I. It is not clear, lawmakers said, if any fees were paid to audit firms in recent years by the committee, or where that money ended up.

“This was a longtime trusted employee and there were no obvious signs that he was living beyond his means,” Mr. Conaway said.

Mr. Conaway said that the many Republican lawmakers who used Mr. Ward for their campaign funds or for bookkeeping for their political action committees were now hurriedly reviewing their own books for evidence of missing money or other improprieties.