The prosecution in the trial of Roger Stone on Wednesday painted President Donald Trump's longtime adviser as a liar in a criminal case stemming from former special counsel Robert Mueller's probe that detailed Russian meddling in the 2016 U.S. election.

After a 12-member jury was selected, opening statements began in the trial in federal court in Washington. The 67-year-old veteran Republican political operative — a self-described "dirty trickster" and "agent provocateur" — has pleaded not guilty to charges of obstructing justice, witness tampering and lying to the U.S. House of Representatives Intelligence Committee.

Stone has been a friend and ally of Trump for some 40 years.