Sen. Richard Blumenthal called for Supreme Court Justice Clarence Thomas to resign after it was revealed that Thomas did not disclose having sold a series of properties to a longtime conservative donor from Texas, according to a investigative report by ProPublica.

"Clarence Thomas should resign because of the sickening appearance of impropriety, taking money, gifts and travel from a billionaire who regularly heads organizations with interests before the court, but there has to be an investigation. This non-disclosure and misreporting should cause his resignation," he said.

Blumenthal said there needs to be a Department of Justice investigation because some of the alleged violations could be criminal.