President Donald Trump routinely makes racist attacks on Warren for saying she has Native ancestry, and says she tried to use her ancestry claims to advance her career. "They're everywhere, and these are serious investigations, so we'll see what happens".
Warren's weekend kickoff saw her formally joining a growing field of candidates for the Democratic Party's presidential nomination as the group competes for the opportunity to unseat Trump.
There are also investigations underway into Trump's business and charity dealings, investigators working out whether he is unjustly profiting from his presidency, and whether he violated campaign finance laws.
Warren's campaign did not inform reporters that she would be attending or speaking at the Tuesday luncheon, instead sharing her prepared remarks - which an aide said she did not deviate from - after the event. "Only under President Trump's leadership will America continue to grow safer, secure and more prosperous".
She said the Democrats will not succeed by just opposing Trump, which will not "make the changes that this country really needs".
Warren has had to apologize for overstating her Native American ancestry.
Elizabeth Warren (D-Mass.) made a surprise appearance at a Native American conference on Tuesday.
Warren officially launched her campaign in MA on Saturday, where she issued a challenge to the super wealthy and called Trump "just the latest and most extreme symptom of what's gone wrong in America".