US prosecutors will drop sexual assault charges against ex-IMF chief Dominique Strauss-Kahn at his next court appearance in two weeks, or earlier, because of doubts about the credibility of the alleged victim, the New York Post said on Tuesday. The newspaper quoted an unnamed top investigator in the case who said the eventual dismissal of charges was “a certainty”. “We all know this case is not sustainable,” The New York Post quoted its source as saying. “Her credibility is so bad now, we know we cannot sustain a case with her,” the source told the newspaper, referring to the Guinean hotel maid who accused Strauss-Kahn of trying to rape her in a luxury hotel in Manhattan. Strauss-Kahn, 62, was arrested on May 14 at New York's JFK airport and subsequently resigned as managing director of the International Monetary Fund. But revelations that the accuser had lied about being raped in Guinea in a US asylum request and changed details of her story about what she did after the incident in Strauss-Kahn's hotel suite have undermined her credibility and left prosecutors struggling to make a case. A judge released Strauss-Kahn from house arrest and lifted strict bail conditions on Friday, although serious charges including sexual assault and attempted rape remain in place.