The probe comes midst George Soros labeling Facebook as a “menace to society”. The probe is aimed at finding out whether Soros shorted the company’s stock.

Following a name calling by billion investor George Soros that Facebook is a “menace to society” Sheryl Sandberg, the social media’s Chief Operating Officer has requested a probe into whether Soros had shorted the company’s stock. Facebook Inc’s board has backed the request.

“To be clear, Sandberg’s question was entirely appropriate given her role as COO,” said Facebook’s board in a letter. “When a well-known and outspoken investor attacks your company publicly, it is fair and appropriate to do this level of diligence.”

The letter was sent by Facebook’s general counsel Colin Stretch to Patrick Gaspard, president of Soros’s Open Society Foundations.

According to the letter, Sandberg said she was unaware whether Facebook Inc had hired a public-relations firm to explore Soros’s criticisms of the company.