The FBI has “concerns about fairness and transparency,” and Sen. Mark Warner, D-Va., plans to call for an investigation after Greenbelt, Maryland, was picked as the FBI’s new home.

FBI Director Christopher Wray told agency staffers that he was concerned about “a potential conflict of interest” involving the selection of the bureau’s new headquarters in Maryland, according to an email obtained by NBC News.

On Thursday, the General Services Administration confirmed that the FBI’s new home would be in Greenbelt, about 13 miles northeast of Washington, seeming to bring to an end a drawn-out and politically fraught site selection process. Two other finalists were Springfield, Virginia, and Landover, Maryland.

In his unusually pointed letter to staffers, Wray said the FBI has “concerns about fairness and transparency in the process and GSA’s failure to adhere to its own site selection plan,” adding that a senior GSA executive overruled a board decision and picked land that is owned by the executive’s previous employer, the Washington Metropolitan Area Transit Authority.

A three-member panel had initially determined that Springfield, Virginia, was the best location. The decision of a political appointee overseeing the process to reject career officials’ “unanimous” recommendation, Wray wrote, wasn’t “‘inherently inappropriate,’ but it is 'exceedingly rare.’”