An investigation by Federal Election Commission attorneys concluded that a fund-raising committee for Senator Clinton’s 2000 campaign either knew that it grossly understated costs for a fund-raising gala or deliberately ignored indications that the event had exceeded its budget.

The committee, New York Senate 2000, “appears either to have been aware of substantial unreported costs or shielded itself from readily available cost information,” the campaign finance regulation agency’s lawyers wrote.

The brief prepared by the general counsel’s office at the Federal Election Commission was made public yesterday after the committee agreed last month to pay a $35,000 civil penalty and to file amended reports showing that the August 12, 2000 gala cost more than $1.2 million, not $519,077 as the committee claimed.

The report alleges that the committee omitted from its public reports hundreds of thousands of dollars of outlays for stage design and construction, invitations, more than 7,000 compact discs given away to donors, and the cost of a chartered jet for Cher and other musicians. Most of the expenses were borne by an Internet entrepreneur, Peter Paul.

“The evidence shows that NYS 2000 was aware that the in-kinds were far in excess of what appeared on its reports,” the attorneys found.

An attorney for the fund-raising committee, Marc Elias, did not return a call seeking comment yesterday afternoon. In a statement last week, he stressed that the commission found no violation of law on the part of Mrs. Clinton or her campaign.

Much of the commission’s report is based on testimony from the May 2005 criminal trial of the campaign’s national finance director, David Rosen, on charges that he caused the submission of false finance reports to federal officials. A judge threw out some of the charges and a jury acquitted Mr. Rosen on the remainder.

“The evidence indicates that Rosen either had knowledge of substantial travel expenses or failed to gather available cost information; there is no evidence that NYS 2000 was denied access to this information,” the commission’s lawyers wrote.

The Federal Election Commission report indicates that the former aide to Mrs. Clinton refused to testify in the commission’s inquiry, citing his Fifth Amendment right against self-incrimination. His attorney, Paul Sandler, did not return a call seeking comment.

The commission attorneys conceded that Paul and other witnesses have criminal records, but the report found that their accounts were corroborated by others with “no apparent motive” to lie. The report concluded that Mr. Rosen was “not liable” under the civil statutes enforced by the commission, but that the committee and its treasurer were responsible for the underreporting.

The commission’s attorneys also noted that press accounts and the complaint which launched the investigation in 2001 gave further notice to the fund-raisers’ about the reporting failures, but that no amended reports were filed.