Donald Trump's next in line for questioning on alleged Russian interference in the 2016 election.
Special Counsel Robert Mueller has been working his way up the chain - interviewing a member of the President's cabinet earlier this week.
It follows his first questioning of a member of the President's cabinet, Attorney-General Jeff Sessions, earlier this week.
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1News US correspondent Rebecca Wright told Kate Hawkesby that Mueller's closing in on whether Trump obstructed justice by firing two key players and the interview could spell the end of Trump's career.
"He's interested in particular in why Trump fired his former FBI director James Comey and what he knew at the time when he fired former National Security Advisor Michael Flynn.
"[It's] absolutely fuelling speculation here that he's closing in on the White House about whether or not Trump tried to shut down this investigation by firing Comey and whether or not that's an obstruction of justice, something the President can be impeached for."
LISTEN ABOVE AS REBECCA WRIGHT SPEAKS WITH KATE HAWKESBY
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