FireEye, an expert in persistent threat detection, and Mandiant, a specialist in cyber threat forensics and endpoint detection, have been teaming up for a little over a year. Now the two companies are merging after FireEye acquired Mandiant for $1 billion.

In the spy vs. spy scenarios sparked by NSA gate and increasing evidence that everyone — not just the NSA — is spying on everyone else, it makes perfect sense that FireEye is buying Mandiant for a cool $1 billion. Mandiant a specialist in cyber threat forensics and endpoint detection came to prominence last year for its starring role in a New York Times report  that linked a Shanghai-based unit of the Chinese People’s Liberation army to cyber attacks on U.S.-based tech companies.