When Donald Trump announced that he was running for president, one of the first issues he raised in his speech was immigration—specifically, the idea that undocumented immigrants are dangerous. “They’re bringing drugs. They’re bringing crime. They’re rapists. And some, I assume, are good people,” he said.

As Trump’s presidency nears its end, his unwavering views on immigration are directly contradicted by a growing body of criminology research. Studies overwhelmingly find no evidence that U.S. immigrants, including those who are undocumented, commit more crimes than native-born Americans. And now a study published in the Proceedings of the National Academy of Sciences USA that draws from a detailed and well-sourced data set comes to an even more dramatic conclusion. It reports that between 2012 and 2018, compared with their U.S.-born neighbors, undocumented immigrants in Texas were less than half as likely to be arrested for violent crimes or drug offenses and less than a quarter as likely to be arrested for property crimes.

“Simply put, we found that undocumented immigrants have lower felony arrest rates than both legal immigrants and, especially, native-born U.S. citizens,” says study co-author Michael Light, a sociologist at the University of Wisconsin–Madison.

Charis E. Kubrin, a professor of criminology, law and society at the University of California, Irvine, who was not involved in the research, describes the paper as “completely groundbreaking.” It’s “another nail in the coffin of what we know about the link between immigration and crime,” she says.

Until now, scientists examining the relationship between immigration and crime had to address the issue broadly in part because many U.S. crime databases do not collect information on immigration status. Research has demonstrated that areas with more immigrants experience no more crime than places with fewer of them and that immigration surges do not lead to increases in illegal activity. The same has been shown to be true for undocumented immigrants in particular.

But as yet studies have not been able to link a specific immigration status to the rates for specific types of crimes. The new paper is among the first to do so. Light and his team were able to delve into the details after learning that the Texas Department of Public Safety had begun cooperating with the Department of Homeland Security to check and record the immigration status of everyone arrested in the state. He asked if the team could have access to the data, and the Texas officials did not object. It was “a eureka moment,” Light says, because with these new data, he knew he and his colleagues could “do some really interesting work.”

In addition to calculating the crime rates of undocumented and legal immigrants, as well as native-born Americans, Light and his team analyzed undocumented immigrants’ relative contribution to felonies in Texas over the studied period. They found that the proportion of arrests involving undocumented immigrants did not increase with time for certain offenses and even decreased for property, drug and traffic crimes.

Estimating the total population of undocumented immigrants in a particular area can be difficult, and Light concedes that the estimates his team used may not be perfect. To account for potential errors, the researchers calculated how inaccurate their population estimates would have to be to change their findings. They found that the undocumented population in Texas would have to be less than half as large as they had estimated for violent crime rates among such immigrants to match those of U.S.-born Americans. The calculation suggests that their findings are “not due to nuances of data or estimation,” says Bianca Bersani, a criminologist at the University of Maryland, who was not involved in the research.

The new study aligns with other research suggesting that immigration-reducing policies do not prevent crime. After the federal government introduced the Secure Communities program, which requires local law enforcement to work with federal immigration officials as a means to expel individuals “who present the most significant threats to public safety,” deportations increased, but crime did not drop. Likewise Kubrin and her colleagues found that when California became a sanctuary state in 2017—limiting state and local police cooperation with federal immigration authorities—crime rates did not rise. “The reality is that immigration policy is not a solution to curb crime,” she says.

Yet Trump has poured resources into the immigration issue. The number of arrests made by U.S. Immigrations and Customs Enforcement (ICE) increased by 30 percent in fiscal year 2017—after Trump signed an executive order giving the agency more authority to detain undocumented immigrants. And in fiscal year 2019 the number of people apprehended at the border between U.S. and Mexico increased to its highest level in 12 years, according to the Pew Research Center.

Researchers are not yet certain why undocumented immigrants are less crime-prone than documented ones or native-born Americans. One contributing factor may be that individuals who emigrate from other countries to the U.S. are highly self-motivated and intrinsically less likely to commit crime. It is also possible that immigrants fear deportation if they are caught, so they are more careful to follow laws. American culture may also play a role. “The longer [immigrants] reside in the United States, the more they adapt to American society, and the more likely their arrest rates resemble those of the native-born,” says Ramiro Martinez, Jr., a quantitative criminologist at Northeastern University.

Although questions on many aspects of the issue remain, what is clear is that the new findings add to a robust body of literature suggesting that undocumented immigrants are not, in fact, criminals. “It’s rare in the social sciences to get such consistent findings,” Kubrin says. “It’s really breathtaking.”