Author Michael Wolff said people in the White House believe that if special counsel Robert Mueller
Robert Swan MuellerSasse: US should applaud choice of Mueller to lead Russia probe MORE looks into President Trump
Donald John TrumpMichelle Wolf in July Fourth salute: 'God bless abortions and God bless America' Graham: Trump's Supreme Court picks 'all winners' Man arrested after allegedly threatening to kill Trump supporters, GOP lawmaker MORE's finances in the Russia probe, the president is "sunk."
"People don't think in the White House — don't think that he colluded with Russia," Wolff, the author of a controversial new book on the Trump White House, said during an interview with CNBC's "Squawk Box."
"They do think that if the investigation goes near his finances, he's sunk."
Wolff also said he was "confident" in the accuracy of everything printed in his book, "Fire and Fury: Inside the Trump White House."
The book, released last week, has sparked controversy. Trump and his allies have criticized the book and sought to defend the president against the allegations made in it.
Mueller is currently investigating Russia's interference in the 2016 presidential election and potential collusion between the Trump campaign and Moscow.
Trump has repeatedly dismissed the Russia probe as a "witch hunt" and denied collusion.
In July Trump warned Mueller against investigating his family's finances beyond the probe into ties between his campaign and Russia.
Last year, former Trump campaign chairman Paul Manafort
Paul John ManafortTrump declares that public opinion has 'turned strongly against' Mueller Ex-GOP majority leader: Republicans must protect Mueller Manafort requests his trial be moved, argues Northern Virginia is too liberal MORE was indicted on charges including conspiracy against the United States, tax fraud and money laundering in connection with the Russia probe.
