Roger Stone arrives in court as criminal trial begins

The criminal trial of President Donald Trump's long-time adviser Roger Stone is set to begin on Tuesday on charges arising from former Special Counsel Robert Mueller's investigation that documented Russian interference to help Trump win the 2016 U.S. election.

The trial could renew attention on efforts by Trump's 2016 campaign to capitalize on emails embarrassing to his Democratic opponent Hillary Clinton that U.S. intelligence officials have concluded were stolen by Russian state-backed hackers. It also coincides with the impeachment inquiry against the Republican president in the House of Representatives over Trump's request that Ukraine investigate a Democratic rival, Joe Biden.

Mueller's investigation, which concluded in March, led to criminal charges against several Trump advisers and campaign aides. Stone is just the second from this group not to plead guilty. Paul Manafort, Trump's former campaign chairman, was convicted by a Virginia jury last year and is now serving a prison sentence of 7-1/2 years.

Stone, a self-described "dirty trickster" and "agent provocateur," has pleaded not guilty to charges of obstructing justice, witness tampering and lying to the House of Representatives Intelligence Committee. That committee is now spearheading the impeachment inquiry.