Trump told Fox News in February that Curiel had been "extremely hostile" toward him, and alleged with no evidence that Curiel was biased against him because of Trump’s political positions on immigration.
"I think it has to do with, perhaps, the fact that I'm very, very strong on the border -- very, very strong on the border," Trump said at the time. "He has been extremely hostile to me. Now, he is Hispanic, I believe."
Pressure on Trump continued to mount after his comments. In an interview with CNN in June, Trump doubled down on his criticism of Curiel, who was born and raised in Indiana, saying that his comments were not racist. "He’s a Mexican. We’re building a wall between here and Mexico."
Trump also used a campaign rally in San Diego, where Judge Curiel serves, to further attack the judge.
"I have a judge who is a hater of Donald Trump, a hater," Trump said last May. "His name is Gonzalo Curiel and he is not doing the right thing."
He went on to say that he believed Curiel was showing bias and that he "happens to be, we believe, Mexican."
I should have easily won the Trump University case on summary judgement but have a judge, Gonzalo Curiel, who is totally biased against me. — Donald J. Trump (@realDonaldTrump) May 30, 2016
Trump later walked back his comments, saying they were "misconstrued as a categorical attack against people of Mexican heritage" in a statement. "I do not feel that one's heritage makes them incapable of being impartial, but, based on the rulings that I have received in the Trump University civil case, I feel justified in questioning whether I am receiving a fair trial."
Curiel has since approved a $25 million settlement deal, which provides compensation to more than 6,000 former students.
Judge Curiel was appointed by President Obama in 2012 to serve on the U.S. District Court in Southern California. He previously served on the San Diego County Superior Court and worked as an Assistant U.S. Attorney.
Trump hasn’t hesitated to attack other members of the federal judiciary since then, blasting members of the Ninth Circuit Court of Appeals after they struck down his travel ban from Muslim-majority countries as unconstitutional.