A US Border Patrol agent charged with allegedly hitting a migrant with a truck had a long history of making hostile statements about border-crossing immigrants, say prosecutors.

Matthew Bowen, 39, allegedly texted another border agent with the message: “PLEASE let us take the gloves off trump!” He also said migrants were “disgusting subhuman s*** unworthy of being kindling for a fire” in November 2017.

Less than two weeks later, prosecutors say, Mr Bowen hit one such migrant with his truck, coming inches away from running the man over – and then lied about the incident in a report.

The texts came to light in filings last month in the US District Court in Tucson, Arizona, as Mr Bowen's lawyer fought to suppress a flurry of messages in which the agent used slurs and made light of violence by agents.

But Mr Bowen's views are hardly extraordinary, argued his lawyer, Sean Chapman. Rather, his sentiments are “commonplace throughout the Border Patrol's Tucson Sector,” Mr Chapman wrote, adding that such messages are “part of the agency's culture.”

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The Tucson Sector of the Border Patrol did not immediately return a message about the texts, though it told The Arizona Daily Star that agents are “held to the highest standards, and any action of misconduct within our ranks will not be tolerated”.

The inflammatory messages are the latest public relations challenge for an overwhelmed agency facing a massive wave of asylum seekers at the southern border and regular allegations from immigration and civil rights groups of abusive behaviour towards migrants.

In the dozens of texts introduced in a 4 April filing, Mr Bowen uses racial slurs and insults like “s*** bags” to refer to migrants. He often used the word “tonk”, which some agents claim is an innocent acronym, the The Arizona Republic reported.

Others say is a slur derived from the sound of hitting an immigrant on the head with a flashlight.

In one text exchange, an unnamed agent asked Mr Bowen, “Did you gas hiscorpse (sic) or just use regular peanut oil while tazing?? For a frying effect.”

Mr Bowen responded: “Guats are best made crispy, with olive oil from their native pais”, using the Spanish word for “country” that doubles as an insult towards Guatemalans, the Daily Star reported. In another text, he refers to “mindless murdering savages”.

The criminal case against Mr Bowen dates to the morning of 3 December 2017, when a US Customs and Border Protection camera operator spotted a 23-year-old Guatemalan man named Antolin Lopez Aguilar, who was suspected of jumping the border fence in Nogales, according to a federal indictment.

As Lopez sprinted to a nearby gas station, Mr Bowen and two other agents responded in separate vehicles.

While one agent hopped out and found Lopez hiding under a semi-truck, Mr Bowen circled the station in his Border Patrol-issued Ford F-150.

When the migrant tried to run back towards the border, prosecutors say, Mr Bowen “accelerated aggressively” in his truck. He hit Mr Lopez twice from behind, knocking him down the second time and screeching to a stop “within inches” of running him over, according to the police.

Mr Lopez was treated at the hospital for abrasions and later sentenced to 30 days in federal prison for illegally entering the country, the Republic reported.

Prosecutors say that Mr Bowen later filed a false report about what happened that morning. In text messages included in the court filing, he repeatedly complains about facing scrutiny over the incident.

“I bumped a guat with a truck while driving about 7 mph,” he wrote in one text. “No injury at all and tonk refused medical.”

In another, he wrote that “If I had to tackle the tonk I would still be doing memos”, adding: “I wonder how they expect us to apprehend wild... runners who don't want to be apprehended?"

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One day after the incident, he texted with Agent Lonnie Swartz, who would later be acquitted of manslaughter for firing 10 rounds into an unarmed Mexican teen as agents were being hit by rocks thrown across the border. He texted Mr Swartz that the incident was “just a little push with a ford bumper”.

Prosecutors have argued in court filings that the texts show that Bowen had “great disdain” for the migrants he policed at the border, the Daily Star reported. But Chapman countered that such language was so common among border agents that they say “nothing about Mr. Bowen's mind-set”.

Mr Bowen has pleaded not guilty to charges of deprivation of rights under colour of law and falsification of records in a federal investigation. Mr Chapman did not immediately respond to a message.

Mr Bowen, who was hired in 2008, was put on indefinite leave without pay after his charges were filed in May 2018. His trial is scheduled to start on 13 August.