In the days following MF Global’s stunning implosion last year, a senior executive at the firm made a startling concession to investigators looking into both the company’s demise and the loss of more than $1 billion in customer money, according to people with direct knowledge of the matter.

MF Global’s chief financial officer for North America, Christine Serwinski, told investigators that her boss, MF Global’s chief executive, Jon Corzine, was well aware of the use and possible misuse of the customer funds during the firm’s final days, and as a result, Corzine may end up in “jail,” these people add.

Serwinski’s initial account of MF Global’s bankruptcy -- and who might be to blame for the loss of $1.6 billion in customer funds -- has yet to be disclosed, and could add a new dimension to the year-long federal investigation into the firm’s implosion.

People with direct knowledge of what Serwinski said to investigators at the Commodity Futures Trading Commission and the CME Group say her statements appear to contradict those made by Corzine when he testified before Congress on the matter. Corzine has told Congressional panels investigating the matter that he never gave “instructions to misuse customer money.”

Several congressional committees investigating the firm’s bankruptcy and the possible misuse of customer money are also aware of Serwinski’s initial account of who might be responsible for the missing funds, these people say.

One committee, the House Financial Services subcommittee on oversight and investigations, is preparing a report on MF Global’s collapse, though it is unclear if the committee will include her statement in the final draft, these people say.

A committee spokeswoman declined to comment.

Serwinski, whose responsibilities included safeguarding customer accounts, has testified before Congress that she was on vacation during the week that led up to MF Global’s bankruptcy, though in contact with people at the firm.

During her testimony at a March hearing of the financial services committee, Serwinski said in a prepared statement “even though the regulations would allow it, I was not comfortable with the firm putting customer funds at risk even just overnight in that manner…I communicated with my office and was assured that the matter was under control and being addressed and that the funds would be returned…”

How she initially came to what appears to be a different conclusion about the possible illegal use of customer funds is unclear; she made her initial statement to investigators from the CFTC and the CME Group in the days following the firm’s bankruptcy. The CME Group (CME), which runs the Chicago Mercantile Exchange, is MF Global’s front-line regulator since the firm had a substantial commodities business used by ranchers and farmer to hedge grain and crop price changes.

In fact it is those ranchers and farmers who are out the bulk of the $1.6 billion in customer funds that remains missing.

Geoffrey F Aronow, an attorney representing Serwinski, wouldn’t deny that his client pointed to Corzine’s possible culpability when interviewed by the CFTC and the CME just after the firm’s demise. A spokesman for the CFTC declined comment.

Steven Goldberg, a spokesman for Corzine, said in a statement that “whatever Ms. Serwinski is alleged to have said in the confusing days following the MF Global bankruptcy, her testimony under oath to the facts was entirely consistent with Mr. Corzine’s.”

Corzine is a long-time staple of Wall Street and national politics; before taking over as chief executive of MF Global in March of 2010, he served as chief executive of Goldman Sachs (GS) and later embarked on a political career with stints as New Jersey Governor and US Senator.

He has also been a major fundraiser for President Obama, and some Congressional Republicans point to his ties to the Obama White House as the reason why he has yet to face even civil charges for the possible misuse of customer funds.

Under securities laws, customer accounts are supposed to be kept separate from firm operations, and there are strict guidelines that firms must follow when using such funds to finance other businesses.

Records show that MF Global started dipping into the customer accounts in late of October of last year after disclosing that under Corzine’s direction the firm had made an outsized bet on the debt of troubled European countries, namely Italy and Spain. With that, lenders began pulling lines of credit and refusing to trade with the firm.

Within a matter of days, MF Global was forced to sell itself or face imminent bankruptcy liquidation. A last-minute sale to Interactive Brokers fell apart when MF Global couldn’t account for around $1 billion in customer funds, forcing its bankruptcy filing on October 31 of last year,  and subsequent liquidation.

Such a loss of customer funds is a nearly unprecedented event at major Wall Street firms. When Bear Stearns suffered a similar fate at the beginning of the 2008 financial crisis, customer brokerage money was kept segregated and safe.

At least one regulator, Terrence Duffy, the executive chairman of the CME, has said the firm’s actions involving customer funds broke the law.

Duffy identified Corzine as knowing “about the loans it had made from the customer segregated accounts” during a Senate agriculture committee hearing in December. During the hearing, he said he made that statement because an MF Global executive had told a CME investigator that “Mr. Corzine was aware of the loans that were being made.”

The MF Global executive that Duffy was referring to was Serwinski, according to people with direct knowledge of the matter. Duffy had been briefed on what she said to the CFTC by his people at the CME who were present when Serwinski was being interviewed, according to people with direct knowledge of the matter.

A spokeswoman for Duffy declined to comment.

A slew of federal agencies are investigating the matter, including the US Attorney in Manhattan, the Securities and Exchange Commission, and the CFTC, the lead regulatory agency of firms that deal in the futures market, as MF Global did before its bankruptcy last year.

Yet, as first reported by the FOX Business Network, federal investigators are facing obstacles in bringing a criminal case against either Corzine or his senior management team. Though neither the criminal nor civil inquiries have concluded, investigators say much of the evidence concerning the missing funds suggests human error, rather than malfeasance.

One potential witness, Edith O’Brien, MF Global’s assistant treasurer, is seeking an immunity deal in exchange for her testimony. O’Brien’s attorney, Reid Weingarten, didn’t return a call for comment.

While Serwinski stopped short of saying Corzine violated the law in her testimony, she has testified before Congress and for a report prepared by MF Global’s bankruptcy trustee James Giddens that she had become increasingly concerned about MF Global dipping into customer accounts for its cash needs even before the firm’s liquidity crisis at the end of last year.

In July of 2011, she told senior management in a memo that “utilizing…the client asset (base) should not be a (broker dealer) working capital source strategy to be relied upon,” according to the Trustee report.

The report added that on August 3, Serwinski’s direct supervisor, CFO Henri Steenkamp, told Serwinski that he was addressing her concerns about the use of customer money. The report said Steenkamp said he “walked Jon [Corzine] through” the regulations involving the use of customer funds.

Serwinski has testified that after returning from vacation in late October of 2011, she at first thought the missing money was the result of an accounting error; she didn’t become aware of the possible misuse of the customer money until October 30 or October 31, when the firm was on the verge of bankruptcy liquidation.

“As Mr. Corzine testified before Congress, he was not aware of any misuse of customer funds until the evening of Sunday October 30th.”said Goldberg, the spokesman for Corzine. “Similarly, Ms. Serwinski testified before Congress that she did not become aware of any misuse of customer money until that same evening.”

Charles Gasparino joined FOX Business Network (FBN) in February 2010 as Senior Correspondent.