We never said we wouldn't poach from Google, says Facebook's Sandberg

Sheryl Sandberg
Chris Ratcliffe | Bloomberg | Getty Images

The first allegations accused Apple's Steve Jobs and Google's Eric Schmidt of entering a secret agreement promising not to poach each other's employees.

Now, the size and scope of this legal case over alleged fixing tech-worker wages in Silicon Valley is expanding. And one major player is getting out in front of the allegations that a hiring conspiracy took place.

Hi-tech hiring conspiracy

CNBC has uncovered a document filed Friday in which Facebook's Chief Operating Officer Sheryl Sandberg filed a declaration with U.S. District Court concerning the tech wage issue.

"In or about August 2008, I was contacted by Jonathan Rosenberg, who was then at Google. Mr. Rosenberg expressed concern about what he described as the perceived rate at which Facebook could hire employees from Google. Around the same time, I also discussed a similar topic with Omid Kordestani, who was also at Google. I declined at that time to limit Facebook's recruitment or hiring of Google employees. Nor have I made or authorized any such agreement between Facebook and Google since that time."

Pando Daily reported this weekend that the tech wage case could be expanding to include Dell, IBM, eBay, Microsoft, Clear Channel, Dreamworks and Comcast, the parent company of CNBC. Pando said the companies could not be reached, or declined to comment.

Apple declined a request from CNBC to comment. Google and Facebook didn't respond to CNBC requests for comment.

(Read more: What the Comcast-Apple TV talks mean)

The case centers around alleged suppressing tech worker wages, and a behind-the-scenes agreement to limit worker mobility and compensation.

An initial hearing will be held Thursday in San Jose with federal Judge Lucy Koh presiding. Jury selection is scheduled to begin May 27.

Tech legal experts tell CNBC there is a good chance this case will never go to trial because many of the companies have already agreed to change their hiring practices.

—By CNBC's Mark Berniker. Follow him on Twitter Twitter @markberniker.