(Bloomberg) – Kazakhstan sued the unidentified hackers who broke into government computers and posted some confidential e-mails officials exchanged with a New York law firm. Kazakhstan has begun an investigation to identify the hackers, according to the complaint.

Kazakhstan declared in the Manhattan federal court complaint that it discovered in late January that its computer system was hacked. Thousands of Kazakhstan officials’ messages sent from Gmail accounts were stolen, according to the complaint filed Thursday. The unauthorized access was discovered at the end of January this year. According to the court files, the stolen Gmail messages were published on various websites, including Facebook.

The hacked messages included some from Marat Beketayev, Kazakhstan’s executive secretary of the Ministry of Justice, and Deputy General Prosecutor Andrey Kravchenko, according to the complaint.

Certain of the stolen messages concerns communications sent to lawyers at Curtis Mallet-Prevost Colt & Mosle LLP, a New York firm hired by Kazakhstan, according to the lawsuit. According to the website of Curtis Mallet-Prevost Colt & Mosle LLP, the firm advised the Republic of Kazakhstan regarding development of the Karachaganak oil and gas field in 2012 and on a settlement agreement with the consortium developing the Kashagan oil and gas field in 2014. It also consulted KazTransOil national company and Samruk Kazyna National Wealth Fund.

Curtis Mallet-Prevost (Kazakhstan) LLP in Almaty and Astana were established in 2008. The firm’s attorneys in the region focus on infrastructure development and public projects, investment management, and international arbitration. They have served as lead advisers on some of the largest projects in Kazakhstan, counselling both private-sector companies and governmental entities.