According to four former intelligence officials, in the 2000s, a staffer in Senator Dianne Feinstein’s San Francisco field office was reporting back to the MSS [China’s Ministry of State Security, its intelligence and security apparatus]. While this person, who was a liaison to the local Chinese community, was fired, charges were never filed against him. (One former official reasoned this was because the staffer was providing political intelligence and not classified information—making prosecution far more difficult.) The suspected informant was ‘run’ by officials based at China’s San Francisco Consulate, said another former intelligence official. The spy’s handler ‘probably got an award back in China’ for his work, noted this former official, dryly.
http://thefederalist.com/2018/08/08/sen-dianne-feinsteins-ties-china-go-way-deeper-alleged-office-spy/