Presumptive Republican presidential nominee Donald Trump ramped up his attacks on the judge presiding over the Trump University case, once again raising the judge’s Mexican ancestry.

Trump said U.S. District Judge Gonzalo Curiel had “an absolute conflict” in presiding over civil fraud proceedings against Trump University because he was “of Mexican heritage,” according to a Wall Street Journal report. Gonzalo was born in Indiana to Mexican immigrant parents.

The billionaire found Curiel’s heritage relevant because Trump campaign rhetoric frequently touts building a border wall between the United States and Mexico.

“I’m building a wall. It’s an inherent conflict of interest,” Trump said.

Last week Trump criticized Curiel at a San Diego speech where he called the judge “a hater of Donald Trump” and “a total disgrace.”

Trump is facing a lawsuit over his for-profit school Trump University, which is alleged by former students to be a scam.

Get our Politics Newsletter. The headlines out of Washington never seem to slow. Subscribe to The D.C. Brief to make sense of what matters most. Please enter a valid email address. Sign Up Now Check the box if you do not wish to receive promotional offers via email from TIME. You can unsubscribe at any time. By signing up you are agreeing to our Terms of Use and Privacy Policy . This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply. Thank you! For your security, we've sent a confirmation email to the address you entered. Click the link to confirm your subscription and begin receiving our newsletters. If you don't get the confirmation within 10 minutes, please check your spam folder.

Contact us at letters@time.com.