New York - Donald Trump said on Friday that the federal judge presiding over a lawsuit brought by former Trump University students has an "absolute conflict" in handling the case because he is "of Mexican heritage".The presumptive Republican presidential nominee told The Wall Street Journal that US District Judge Gonzalo Curiel has "an inherent conflict of interest" because Trump is "building a wall", a reference to Trump's proposal to build a wall along the border between the US and Mexico.Trump University is the target of two lawsuits in San Diego and one in New York that accuse the business of fleecing students with unfulfilled promises to teach secrets of success in real estate. Trump has maintained that customers were overwhelmingly satisfied with the offerings.Trump has brought up Curiel's ethnicity several times this year, including last week at a rally in San Diego. Curiel was born in Indiana and served as a federal prosecutor and a judge in the California state judicial system before being nominated to the federal bench by President Barack Obama in 2011.On Wednesday, Curiel ordered some records that were released in the class action lawsuit against Trump University be yanked from public view. Late on Tuesday, Curiel ordered some released documents to be resealed and resubmitted with sections blacked-out. He said some records had "mistakenly" been released last week, when he ordered some documents made public.Lorella Praeli, director of Latino outreach for Democrat Hillary Clinton's campaign, said on Friday that Curiel and his family "epitomise the American dream"."The fact that Donald Trump doesn't see Judge Curiel and his family as Americans makes him unfit to be president of this great nation, a nation of immigrants," Praeli said in a statement.