Image copyright EPA Image caption Judge Gonzalo Curiel (L) was called a "hater" by Mr Trump

A US judge labelled "Mexican" by President Donald Trump last year is to hear a high-profile deportation case.

Judge Gonzalo Curiel, whom Mr Trump also called a "hater", was apparently assigned to the lawsuit randomly.

The case involves Juan Manuel Montes, who says he was deported from California in February, though he has lived in the US since he was a child.

But US immigration officials say the 23-year-old voluntarily left the US for Mexico.

The lawsuit has been seized upon by immigration advocates and critics of the president as proof that his administration is arbitrarily deporting US residents.

What is the Montes case?

Lawyers for Mr Montes, who lived in the US since he was nine years old, say he was deported on 17 February after he was stopped in the border city of Calexico, California, by Border Patrol officials.

He said he had left his wallet and identification in a friend's car.

Image copyright National Immigraiton Law Center Image caption Juan Manuel Montes says he was deported from Calexico, California

The plaintiff says he made clear he was protected from deportation under Deferred Action for Childhood Arrivals (Daca), an Obama-era programme allowing immigrants brought illegally to the US as children to stay.

But Mr Montes - who has a cognitive disability from a brain injury - says he was deported to Mexico anyway.

However, the Department of Homeland Security (DHS) says it has no record of Mr Montes being deported on 17 February.

The DHS says it does have a record, however, of arresting Mr Montes on 19 February after he climbed a border fence to try to get back into the US from Mexico. He was sent back.

Mr Montes and his lawyers concede he did climb over the border fence, but only because he had been unfairly deported in the first place.

Image copyright Getty Images Image caption A band plays to traffic on the Mexico side of the border fence, as seen from Calexico, Californi

Who is telling the truth?

The case hinges on whether the 17 February encounter alleged by Mr Montes ever happened.

If not, then he was not protected under Daca, because he would have left the US without permission and then tried to re-enter illegally.

The DHS has already corrected one detail of its records - the department originally said Mr Montes' Daca enrolment had expired in 2015, but it acknowledged on Wednesday that his status was valid until 2018.

However, the agency also said Mr Montes had "lost his Daca status when he left the United States without [permission from immigration authorities] on an unknown date prior to his arrest" by Border Patrol on 19 February.

Activists have seized on the case to argue that the Trump administration is going back on its word not to deport more than 750,000 immigrants awarded Daca status.

They say Mr Montes may be the first "Dreamer", as Daca enrolees are known, deported under Mr Trump's presidency.

Who is Judge Gonzalo Curiel?

US District Judge Gonzalo Curiel presided last year over a lawsuit involving students who claimed fraud after paying to attend real estate seminars branded as Trump University.

During the lawsuit, Mr Trump said Judge Curiel's "Mexican heritage" meant that he would not rule fairly in the case, because Mr Trump wanted to build a border wall between the US and Mexico.

Image copyright Getty Images Image caption Copies of How To Build Wealth, audio business courses created for Trump University

Mr Trump was condemned by Democrats and Republicans alike for his attacks on the jurist, who was born in Indiana to Mexican parents.

Judge Curiel later approved a $25m (£23.3m) settlement in the case, under the terms of which Mr Trump did not admit any wrongdoing.

His assignment to the Montes case is said to be purely coincidental, based on rules for the Southern District of California, which selects judges on a rotating schedule.

Judge Curiel will be asked to decide whether US Customs and Border Protection should release information on Mr Montes' deportation to his lawyers.

No court date has been set.

More on Trump and immigration