Facebook founder Mark Zuckerberg has a new whistleblower and this appears to be serious.   According to Business Insider:  Sophie Zhang, a former Facebook data scientist who went public with her criticisms of the company in September 2020, has told CNN she is willing to testify before Congress.  Zhang also said on Twitter on Sunday that she had provided a US law-enforcement agency with "detailed documentation regarding potential criminal violations."  When asked by CNN, Zhang did not say which agency she gave documents to. An FBI spokesperson declined to comment when contacted by CNN.  "If Congress wishes for me to testify, I will fulfill my civic duty, as I've publicly stated for the past half year," Zhang said in a tweet Monday that linked to her CNN interview.