Story highlights Brian Benczkowski served in the Justice Department under President George W. Bush

He also led the Trump-Pence transition team at the Justice Department

(CNN) President Donald Trump's nominee to head up the criminal division at the Justice Department has disclosed to members of the Senate judiciary committee that he previously represented a Russian bank whose computer server activity has been under scrutiny by FBI counterintelligence.

Brian Benczkowski served in the Justice Department under President George W. Bush and is currently a partner at Kirkland & Ellis LLP. He told senators in a letter obtained by CNN that he specifically disclosed his law firm's representation of Alfa Bank in connection with completing his SF-86 security clearance form.

Questions about the bank's activity first arose last year when a group of computer scientists raised concerns about internet records that showed that Alfa Bank servers repeatedly looked up the unique internet address of a Trump Organization computer server in the United States.

The bank later hired a cybersecurity firm called Stroz Friedberg to investigate unusual computer server activity, and background materials submitted to senators by Viet Dinh , one of Benczkowski's partners at Kirkland, now show Benczkowski supervised that project.

Dinh, also a former DOJ official, further defended the bank in a letter accompanying the submission to senators.

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