Charges against Dominique Strauss-Kahn, the former IMF chief accused of sexually assaulting a maid in a Manhattan hotel room, have been dropped. Judge Michael J. Obus of the State Supreme Court dropped the charges at the request of prosecutors at the office of Manhattan district attorney Cyrus R. Vance, Jr. In a lengthy legal brief filed Monday, the district attorney’s office said it had no reasonable chance of obtaining a conviction. The case against Strauss-Kahn collapsed after prosecutors grew concerned about the reliability of the alleged victim, Nafissatou Diallo. “In virtually every substantive interview … she has not been truthful,” the brief says. “If we do not believe her beyond a reasonable doubt, we cannot ask a jury to do so.” Strauss-Kahn still faces a civil suit launched by Diallo, but he has been released and is now free to return to France.