[Note - Pay close attention to dates, names in descriptions amid all citations]
Sources: โฆ In 2013 the U.S. Department of Justice, Southern District of New York, announced an indictment against a Russian Operative Evgeny Buryakov. LINK HERE. In March of 2016 Buryakov pleaded GUILTY:
Preet Bharara, the United States Attorney for the Southern District of New York, and John P. Carlin, Assistant Attorney General for National Security, announced that EVGENY BURYAKOV, a/k/a "Zhenya," pled guilty today to conspiring to act in the United States as an agent of the Russian Federation, without providing prior notice to the Attorney General.โฆ In 2016 Reuters published an article, based on the ongoing court case, going into detail about court records and how the FBI built their case. Reuters also describes the FBI UCE-1 (Under-Cover Employee) with strong detail. LINK HERE.
[...] The FBI obtained the recordings after Sporyshev attempted to recruit an FBI undercover employee ("UCE-1"), who was posing as an analyst from a New York-based energy company. In response to requests from Sporyshev, UCE-1 provided Sporyshev with binders containing purported industry analysis written by UCE-1 and supporting documentation relating to UCE-1's reports, as well as covertly placed recording devices.(more)
Comment: More details on Page's work for the FBI, from Townhall: