[ by Howard Haykin ] I got plenty of nothing / And nothing's plenty for me... [lyrics from Porgy and Bess, by Hayward, Gershwin & Gershwin] "... Still got no billion / Got no clues / Got nobody to blame!" [lyrics from Compliance Insights] FYI: this story originally was to be entitled, "What a Crime - No MF Global Criminal Charges." While any of the titles seem to work, it's a mystery what work was accomplished by federal investigators.  It's now 10 months after the brokerage firm MF Global collapsed, and the firm's balance sheet was short something like $1 billion in customer money. With the criminal investigation heading into its final stage, the mystery remains unsolved, there appear to be few credible clues, and it's now expected that no criminal charges will be made against any top executives. Instead, criminal investigators are concluding collectively guessing that chaos and porous risk controls at the firm, rather than fraud, allowed the money to disappear, according to people involved in the case. Clueless Again! It was anticipated that building a criminal case would be difficult - made all the more difficult by the carefully rehearsed testimonies of executives.  All this is not going to go down well with Washington or the American populace.  Were there really no staffers in New York or Chicago or elsewhere who recalled receiving instructions or authorizations from an executive mentioned anything about using customer funds, which the firm would replenish after the storm had passed? In the most telling indication yet that the MF Global investigation is winding down, federal authorities are seeking to interview former CEO Jon Corzine next month, according to the people involved in the case.  Authorities hope that Mr. Corzine, who is expected to accept the invitation, will shed light on the actions of other employees at MF Global. Those developments indicate that federal prosecutors do not expect to file criminal charges against the former New Jersey governor.  Mr. Corzine has not yet received assurances that he is free from scrutiny, but two rounds of interviews with former employees and a review of thousands of documents have left prosecutors without a case against him, say the people involved in the investigation who spoke on the condition of anonymity. While the government's findings would remove the darkest cloud looming over Mr. Corzine - the threat of criminal charges - the former Goldman Sachs chief is not yet in the clear.  A bankruptcy trustee on Wednesday joined customers' lawsuits against Mr. Corzine, and regulators are still considering civil enforcement actions, which could cost him millions of dollars or ban him from working on Wall Street. Corzine Hedging His Bets. Mr. Corzine, in a bid to rebuild his image and engage his passion for trading, is weighing whether to start a hedge fund, according to people with knowledge of his plans. He is currently trading with his family's wealth.  If he is successful as a hedge fund manager, it would be the latest career comeback for a man who was ousted from both the top seat at Goldman Sachs and the New Jersey governor's mansion. Suspect List May Be Down to One. As the government's focus shifts away from Mr. Corzine, it remains interested in a lower-level employee in the firm's Chicago office, who was known as the "keeper of the books" at MF Global. That employee, Edith O'Brien, oversaw the transfer of customer money during the firm's final week, when the client cash vanished into the hands of banks, clearinghouses and even other customers. Ms. O'Brien, an assistant treasurer, has declined to cooperate with authorities without receiving immunity from criminal prosecution.  The government is hesitating to grant her request, suspecting that Ms. O'Brien is the highest-ranking employee with potential liability, one of the people involved in the case said.  Ms. O'Brien has not been accused of any wrongdoing. If Mr. Corzine agrees to a meeting next month with the FBI and federal prosecutors, the authorities are expected to question him about his interactions with Ms. O'Brien.  But Mr. Corzine is unlikely to offer damning evidence or a critical view of Ms. O'Brien, another person briefed on the matter said.  The statements Mr. Corzine provides cannot be used against him under the expected terms of the interview, but authorities can use it to build their broader case.  And if Mr. Corzine were to arouse suspicions during the interview, he could find himself a target. Mr. Corzine has already given his version of events publicly. In Congressional testimony last year, he detailed an exchange he had with Ms. O'Brien days before the firm's collapse.  The back and forth involved a $175 million transfer to JPMorgan Chase to cover an overdrawn account.  The transfer, it turned out, came from customer money. But internal e-mails suggest that Mr. Corzine did not know the origin of the funds.  An e-mail reviewed by The New York Times shows Ms. O'Brien explicitly stated that the money belonged to the firm, not customers.  It is possible that with the books in disarray, Ms. O'Brien was not aware that customer money was in jeopardy. While Mr. Corzine also testified that he never authorized or intended to authorize the misuse of customer money, his risky trading strategy helped pave the firm's downfall.  But that is not grounds for a criminal conviction - let alone a criminal indictment. For further detail, go to:  [Dealbook, 8/15/12].