It's not like Vladimir Putin needs to be subtle at this point. CNN:
[Paul] Whelan was arrested Friday in Moscow on suspicion of carrying out an act of espionage, Russia's Federal Security Service (FSB) has said. No further details about the circumstances of his arrest or the allegations against him have been released.
His family rejects notions that he was a spy, asserting that the well-traveled, discharged Marine reservist was in Russia to attend a wedding for a fellow former US service member and a Russian woman.
Earlier Wednesday, US Secretary of State Mike Pompeo said his government has made clear to Russia that the US expects to learn more about the charges.
Bill Browder appeared on CNN.
"Paul Whelan I believe was taken as leverage for Vladimir Putin in response to the Maria Butina prosecution in Washington. ...[Putin] was in a very weak position. He needed to change that... So he looked for a hostage."
He also tweeted a warning to travellers:
It's also not clear how much "leverage" Trump has to get an American hostage back from Putin, or what he can do regarding Maria Butina's guilty plea that isn't just more obstruction of justice.