President Trump slammed tax day protesters on Sunday, tweeting, "the election is over!"

In the wake of protests urging Donald Trump to release his tax returns, the president posted a series of tweets on Sunday.
The first tweet read, "I did what was an almost an impossible thing to do for a Republican-easily won the Electoral College! Now Tax Returns are brought up again?"
A few minutes later, he tweeted, "Someone should look into who paid for the small organized rallies yesterday. The election is over!"
Meanwhile, Senator Elizabeth Warren said in a recent MoveOn.org video, "Donald Trump is hiding something. And we know where he’s hiding it: not in a safe, not in a vault. Nope, he’s hiding it in his taxes."
The Trump administration has continued to claim ongoing audit as the reason for not releasing his tax returns.
In late January, White House counselor Kellyanne Conway tweeted, “On taxes, answers (& repeated questions) are same from campaign: POTUS is under audit and will not release until that is completed. #nonews.”