The U.S. Securities and Exchange Commission’s enforcement action against an accused insider trader appears to have unraveled, as the agency admitted Monday that it can’t produce two key witnesses to testify about an alleged tip-off regarding Herbalife Ltd.

The SEC moved to dismiss its own case against Jordan Peixoto, who was accused in a September administrative complaint of unlawfully shorting Herbalife stock two years ago. The SEC alleged that Peixoto based his trades on an inside tip he received shortly before prominent hedge fund manager William Ackman made a presentation panning Herbalife as a pyramid scheme.