A conspiracy theorist touted by President Donald Trump as a voter fraud expert has failed to provide any evidence backing up his claims that millions of people voted illegally in the presidential election.

The country learned Gregg Phillips’ name on Friday, when Trump cited him in a tweet as an authority on the massive voter fraud that supposedly took place during the 2016 election. In reality, voter fraud on such a huge scale would be incredibly difficult to pull off.

Look forward to seeing final results of VoteStand. Gregg Phillips and crew say at least 3,000,000 votes were illegal. We must do better! — Donald J. Trump (@realDonaldTrump) January 27, 2017

In media interviews, Phillips, 57, has said he’s a bit stunned that Trump cited him in a tweet and stated as fact that 3 million votes were cast illegally — which happens to be roughly the same number of popular votes that former Secretary of State Hillary Clinton won over Trump.

Phillips is a former deputy commissioner at the Texas Health and Human Services Commission. He has a checkered past, including accusations of ethics breaches in his work for two state governments. He owes more than $100,000 in unpaid federal taxes, according to an IRS lien, The Guardian reports.

He is also the creator of VoteStand, which he describes as an “anti-vote-fraud app.” After the presidential election in November, he declared there’d been widespread voter fraud.

But Phillips has been roundly denounced as a conspiracy theorist by academics and others who study voting. Phillips has claimed that former President Barack Obama’s Department of Homeland Security hacked the election. He has also said that “Israelis impersonated Russians” and interfered with the election, The New York Times reports.

Phillips offered a weak defense of himself in an interview Friday with ABC News. “I may be a wacko, I may be a nut, I don’t know,” he said. “I don’t really care what they say about me.”

When asked what facts he has to support his claim that millions of people voted illegally, Phillips said he is “building that case right now.”

Earlier on Friday, before Trump’s tweet, Phillips claimed to CNN that he has the names of 3 million people who voted illegally — but that he needs more time to prepare a report.

He told ABC he was taken aback that he’d appeared in a Trump tweet. “That was a little unexpected,” he said. “I mean, I’m just a regular guy and all of a sudden the president tweets my name and my whole world lit up for a little while today.”

Trump should have examined a bit more of Phillips’ past. Besides the IRS lien — he insists he actually owes less than $50,000, despite what court records say ― he has also been in trouble with state authorities. He has been accused of financially rewarding associates while serving in state government positions in both Mississippi and Texas, according to The Daily Beast.

A 1995 document by the Mississippi Legislature’s Joint Committee on Performance Evaluation and Expenditure Review accuses Phillips of ethics violations and says his actions “facilitated an erosion of the public trust.” In 2005, the Houston Chronicle reported that Phillips had “played a role in a major state contract” being awarded to a former employer. A spokesman for the Texas comptroller told The Daily Beast that Phillips is no longer allowed to do business in the state.

Trump has so far failed to present a shred of evidence to support his claim that an election he won was corrupted by as many as 5 million illegally cast votes. Witnesses told The New York Times that Trump offered a single anecdote to back his claims to congressional leaders on Friday. He said that professional golfer Bernhard Langer told him that he was turned away at the Florida polls, while other people ― who Trump said looked suspicious ― were allowed to cast provisional ballots.

But Langer later told the media that he is a German citizen and is not allowed to vote in the U.S., and that he’d passed along a story he had heard from a friend to another friend, who had apparently passed it on to Trump. He blamed the media for the “mischaracterization” of Trump’s story.

Voter fraud “has been studied,” Gerald Hebert, director of the Voting Rights and Redistricting Program at the Campaign Legal Center in Washington, D.C., told ABC.

“This isn’t just me theorizing about this,” Hebert said. “This has actually been studied, and it just doesn’t exist.”

On Wednesday, Trump tweeted that he would order the federal government to investigate voter fraud.