WASHINGTON — As tanks, artillery and combat troops streamed from Russia into Ukraine in 2014, the United States government dispatched a multiagency team of technical experts to Kiev to help the fragile government there shore up its energy supply for the coming winter.
The head of that team, William N. Bryan, was a career civil servant with an expertise in energy infrastructure and security.
But he was a neophyte when it came to the notoriously factional and corrupt world of Ukrainian politics. And it was not long before American and Ukrainian government officials began raising concerns that he was being co-opted by a Ukrainian company seen as aligned with a prominent oligarch — concerns that grew when Mr. Bryan later joined a consulting firm that pursued business proposals with the company.
Now, four years later, those relationships are attracting new scrutiny as Mr. Bryan awaits a Senate confirmation vote to become President Trump’s homeland security under secretary for science and technology.