HOUSTON Police Department chief Art Acevedo remembers the day when a little boy came up to him with tears in his eyes.

“I’m afraid to go to school because when I come home my parents will be gone,” the boy told him.

He also tells the story of an 18-year-old — who finished top of the class at his high school and went on to complete a mathematics degree, graduating with honours — who also approached him with tears in his eyes.

“I really wanna be a police officer but I’m an undocumented immigrant. My parents brought me here when I was three,” the teen told Mr Acevedo.

These moments are indicative of a fear that is sweeping America.

The US is home to a staggering 11.3 million immigrants who are essentially living in the country illegally.

And since Donald Trump branded Mexican immigrants as criminals and rapists, and was swept to power promising to build a wall on the US’s southern border, these 11.3 million people have crept into the shadows for fear of being kicked out of the country.

Now the President has set his sights on America’s “sanctuary cities” — such as San Francisco, New York and Los Angeles — that are openly defying policies designed to rid the nation of these undocumented immigrants.

Mr Trump says sanctuary cities have “caused so many needless deaths” by providing safe haven to people who he sees as violent menaces.

He has signed an executive order that cuts off funding to cities that refuse to co-operate with Immigration and Customs Enforcement (ICE), the American version of the Australian Border Force.

But the leaders of these cities say that Mr Trump’s policies have actually made their communities more dangerous — and they are refusing to obey their commander-in-chief.

In Texas, it is illegal for police not to co-operate with immigration agents. Yet, that is exactly what Mr Acevedo is ordering his officers at the Houston Police Department to do.

His department was happy to help ICE deport undocumented immigrants who were violent criminals, but he refuses to assist them going after law-abiding residents.

Mr Acevedo said the fear that was gripping Houston was “heartbreaking”.

“When I have little kids coming up to me with tears in their eyes and their parents with them and telling me ‘I’m afraid to go to school because when I come home my parents will be gone’, what do you say to that child? The father’s not a Crip out stealing but they’re making a living, which is how we’re wired as human beings,” he said at a conference held by The New York Times this week.

“The fear is real, it’s palpable.”

Mr Acevedo said the reporting of sexual assaults among the Hispanic community had dropped by 42.8 per cent in the first three months of the year, compared to the same period in 2016, while crime affecting the rest of the city’s population had risen.

“Now, you explain to me, political leaders, how does that benefit the American people when crimes going up for everyone else except the Hispanics?” said Mr Acevedo, who came to the US from Cuba in 1968 as a political refugee.

“If you lose 11 million victims and witnesses, the unintended consequences are that we are all less safe.

“Nobody wants criminal aliens that are out committing violent crimes to remain in this country … so let’s have public policy that based on what’s good for the American people and not what’s good for the next primary election.”

Mr Acevedo said the story of the 18-year-old who aspired to be a police officer had stuck with him.

“They’re talking about getting rid of these kids. Now, why would we want this kid, who’s as American as they come, why would we deport them?” he said.

“Especially when you look at the fact that the birthrate is declining around the world, we’re not only going to need immigrants, we’re going to have to start competing for immigrants and, quite frankly, we’re starting to see, because of the ugliness of the debate here, immigrants, they have choices.

“They can go to Canada, they can go to Australia and New Zealand, they can go all over the world.

“The rest of the world has caught up and if we’re not smart we’re not going to be able to compete in a global economy because of the ugliness of this entire debate.”

Ras Baraka, the mayor of Newark, New Jersey, a racially diverse city just over the river from New York, said Mr Trump was “completely off the mark” when he argued that kicking out undocumented immigrants would stop violence.

“They’re threatening to take away cops’ grants if you don’t comply with the order, which means that they’re reducing the number of police officers in cities that say they want to become sanctuary cities,” he said.

“In places like Newark, immigrants are more victims than they are perpetrators of crime, so they become victims of crime, easy targets who do not report to police the kind of abuse and attacks that they get because they are afraid they’ll be deported.

“They don’t come to court, they don’t report it to the precinct … It’s easier for police officers to do their job when they can get the immigrant communities and undocumented communities to begin to co-operate and respond to police departments and the city agencies without fear of retribution.”

Mr Baraka said the fear in his community had created a “dangerous environment”.

“The demonisation of entire communities, entire religions and entire folks is really what has people on edge and have people that work at city hall and who are doctor students saying ‘Am I going to lose my job tomorrow? Am I going to be deported?’” he said.

“We have parents who are refusing to send their kids to school.

“We established a municipal ID in the city and folks are now even afraid to come and get the municipal ID because they think it’s a ploy to get people to come to the city and turn them over to ICE.

“After we spent so much time trying to pull people out of the shadows, people are returning back because of the environment that’s been set here.”

Mr Acevedo said the police force had been calling for immigration reform for 15 years that could provide undocumented immigrants a path way to obtaining citizenship.

“These people don’t care about voting, these immigrant communities, what they care about is legitimacy.

“They want to come out of the shadows; they want to fully participate.

“These are real people. We’re supposed to be a Judaeo-Christian society and yet we don’t deal with people that put food on our table, that do a lot of jobs that nobody wants to do.”

Houston has one of the largest populations of undocumented immigrants in the US, just behind New York and Los Angeles.

So what would happen to the city if all of them were kicked out?

“It would be an economic disaster for the city of Houston. And that’s the hypocrisy,” Mr Acevedo said.

“We’re all being played; it’s all political theatre.

“The truth of the matter is that if you wanted to get rid of undocumented immigrants you’d go after the employers but they don’t do that because they realise that when 60 per cent of the people putting up buildings in the city are undocumented.”

Mr Baraka said a Newark without undocumented immigrants would be a “very boring city, that’s for sure”.

“All of the mum and pop shops, the economy would be affected. The diversity that we have, all that stuff would disappear almost immediately. Whole sectors of our community would be gone because the immigrant community has moved out. It would be an economic disaster,” he said.