The letter from the U.S. attorney's office for the Northern District of California does not specify exactly what is being investigated, but said that a former Uber employee revealed in an interview that the company had failed to disclose additional evidence to investigators.
The letter to U.S. District Judge William Alsup is the government's first public acknowledgement that it is conducting a criminal probe of Uber.
The letter was released as part of a legal dispute between Uber and Waymo, a self-driving car developer owned by Google's parent company. In that case, Waymo alleges that Uber stole trade secrets by hiring one of its former employees.
