( CNN) The FBI employed techniques reminiscent of Cold-War spy tactics to eavesdrop on Russian intelligence agents in New York City: bugging binders full of “confidential” industry information, court documents exposed this week.

The covert practice was indicates that there is filings for the trial of Evgeny Buryakov on Tuesday, who was arrested in January 2015. Attorneys is argued that Buryakov posed as an employee for a Russian Bank in New York City but was actually working for the Russian foreign intelligence agency, SVR.