As federal prosecutors issued a subpoena seeking documents from Donald Trump's inaugural committee, here's what may lie ahead for him.
What's it all about?
Special counsel Robert Mueller is looking into whether the Trump campaign coordinated with Russia to impact the outcome of US elections and whether the president obstructed the investigation.
Trump also plays a central role in a separate case in New York, where prosecutors have implicated him in a crime. They say Trump directed his personal lawyer Michael Cohen to make illegal hush-money payments to two women as a way to quash potential sex scandals during the campaign.
What's relevant for now?
So far, Mueller has charged 34 people, including several close to the president. But he has yet to accuse anyone close to the Trump campaign of conspiring with the Kremlin to hurt Democrat Hillary Clinton and help Trump win the election.
On Monday, a federal judge set a March 13 sentencing for former Trump campaign chairman Paul Manafort on two felony charges stemming from witness tampering and crimes related to his Ukrainian political work.
Roger Stone, a longtime Trump adviser and confidant, was the latest in Trump's circle to face charges. The political operative is accused of lying to lawmakers, engaging in witness tampering and obstructing a congressional investigation into possible coordination between Russia and Trump's campaign. He pleaded not guilty last week.
In a separate case, federal prosecutors in New York issued a subpoena Monday seeking documents from Trump's inaugural committee, furthering a federal inquiry into a fund that has faced mounting scrutiny into how it raised and spent its money.
Inaugural committee spokeswoman Kristin Celauro said the committee received the subpoena and was still reviewing it.
Did the Trump campaign collude with Russia?
There is no smoking gun when it comes to the question of Russia collusion. But the evidence so far shows that a broad range of Trump associates had Russia-related contacts during the 2016 presidential campaign and transition period, and several lied about the communication.
There is also evidence that some people in the president's orbit were discussing a possible email dump from WikiLeaks before it occurred. American intelligence agencies and Mueller have said Russia was the source of hacked material released by WikiLeaks during the campaign that was damaging to Hillary Clinton's presidential effort.
What about obstruction of justice?
That is another unresolved question that Mueller is pursuing. Investigators have examined key episodes such as Trump's firing of FBI director James Comey and his fury over the recusal from the investigation by then-attorney general Jeff Sessions.
What does Trump have to say?
Trump has repeatedly slammed the Mueller investigation as a "witch hunt" and insisted there was "NO COLLUSION" with Russia. He also says his former lawyer, Cohen, lied to get a lighter sentence in New York.
When does this all end?
Acting Attorney General Matthew Whitaker says the probe is "close to being completed" — the first official sign that Mueller's investigation may be wrapping up. But he gave no specific timetable.