Microsoft snooped on blogger's Hotmail to track who was leaking company secretse

The email search uncovered messages from Kibkalo to the blogger containing fixes for the Windows 8 RT operating system before they were released publicly. The complaint alleges Kibkalo also shared a software development kit that could be used by hackers to understand more about how Microsoft uses product keys to activate software.

Besides the email search, Microsoft also combed through instant messages the two exchanged that September. Microsoft also examined files in Kibkalo's cloud storage account, which until last month was called SkyDrive. Kibkalo is accused of using SkyDrive to share files with the blogger.

Kibkalo has since relocated to Russia, the FBI complaint says.

Frank said in his statement that no court order was needed to conduct the searches.

"Courts do not issue orders authorising someone to search themselves," he said. "Even when we have probable cause, it's not feasible to ask a court to order us to search ourselves."

Hotmail's terms of service includes a section that says, "We may access or disclose information about you, including the content of your communications, in order to ... protect the rights or property of Microsoft or our customers."

Redmond, Washington-based Microsoft has taken a defiant stand against intrusions of customer privacy, in the wake of National Security Agency systems analyst Edward Snowden's revelations of government snooping into online activities.

General counsel Brad Smith said in a blog post in December that Microsoft was "especially alarmed" at news reports of widespread government cyber-spying.

Microsoft also has a long-running negative ad campaign called "Scroogled," in which it slams Google for scanning "every word in every email" to sell ads, saying that "Google crosses the line."