U.S. Immigration and Customs Enforcement has been making news with its brutal crackdowns on immigrants. Arrests of men and women with no criminal record are up 142% since January 2017. In December, the federal inspector general found widespread civil rights abuses at ICE detention centers. Last month, ICE agents rounded up workers at 7-Elevens, and the director of ICE, Tom Homan, has promised more such raids.

We hear daily horror stories of longtime U.S. residents torn from their families: Edwin Marcial, father of four, who worked for 15 years at my neighborhood brunch spot, the New York Bagel Co. in Brentwood, got detained in December. Stories like Marcial’s abound: Jorge Garcia, a 39-year-old father of two from Detroit was deported to Mexico on Martin Luther King Jr. Day. Green-card holder Dr. Lukasz Niec, who has lived in the U.S. since he was 3, faces deportation for misdemeanors committed 25 years ago, when he was a teenager.

ICE’s deportation zeal stands in contrast to a particularly shameful chapter in its history. When it was known as the U.S. Immigration and Naturalization Service, from 1945 to 1979, it repeatedly failed to investigate and remove European war criminals from the U.S. And that included Holocaust perpetrators.

The re-opening of our borders in the years following World War II allowed thousands of collaborators and accomplices of the Nazi regime to make their way to the United States. A small number of them were knowingly brought in by U.S. intelligence services. Most came through the system undetected amid an influx of nearly 400,000 war-displaced persons. At the time, officials set a preposterously high bar for complicity in war crimes. That, combined with an initial lack of knowledge about the Holocaust, made it easy for applicants to cover up their backgrounds on their immigration forms.

Once here, it was as easy to escape justice. Adrija Artukovic, minister of the Interior and Justice in Croatia during the war, sneaked into the U.S. under an assumed name in 1948 and settled in Seal Beach. Known in Yugoslavia as the Butcher of the Balkans, Artukovic was described by a U.S. official as Croatia’s Himmler. American authorities knew he was here as early as 1949, but he wasn’t arrested and returned to Croatia for trial until the 1980s. His death sentence was never carried out; he died in 1988.

For the first two decades after World War II, the INS brought very few "denaturalization" cases to court, a total of five for the entire 1950s. Only one of these war criminals was successfully denaturalized. The 1960s saw just two cases pursued, despite INS being flooded with dozens if not hundreds of tips on potential war criminals living among us. The cases it did manage to bring to court in the 1950s and 1960s were so poorly constructed that even a Romanian Iron Guard member and virulent anti-Semite, Valerian Trifa, was not stripped of his citizenship. As for deportations, the INS filed no more than 10 cases against suspected war criminals from 1945 to 1973.

It’s possible that skin color and country of origin played a role in the INS’s lack of interest in investigating the war records of newcomers from places like the Baltics and Ukraine. They blended in, and records show that INS agents at every turn had a hard time seeing these immigrants as dangerous. They humanized them, and so did others, even after evidence emerged to the contrary. A suspected Nazi unit commander was identified in a Minnesota newspaper as a "pillar of the church" and a man who "takes care of his yard and walks with his wife." A concentration camp guard living in New York was referred to as a "feeble old man" by neighbors.

The Kowalchuk brothers, Sergei and Mykola, of Philadelphia, served together in an auxiliary police force in the Ukrainian town of Liuboml, where more than 4,000 Jews were killed. Sergei was chief of police. In 1966, an INS investigator noted that Mykola’s Jewish boss told an interviewer he could not believe his employee was complicit in wartime violence, as if such a comment from such a source should be considered exculpatory. In a New York Times article, a police officer and neighbor of Kowalchuk’s said, "They are good people from what I can see. They get up early in the morning and work hard every day."

It took the heroic efforts of two members of Congress, Elizabeth Holtzman (D-N.Y.) and Joshua Eilberg (D-Pa.), aided by Jewish organizations and journalists, to call the INS to account for its failure to pursue war criminals. Congressional hearings in the 1970s demonstrated how often the agency had failed to act on tips and how badly it botched investigations. Holtzman admonished INS for its "appalling laxness and superficiality."

The hearings resulted in the establishment of an Office of Special Investigations in the Department of Justice specifically to find and remove war criminals. Still, the INS was not particularly cooperative: One document shows officers mocking the new office, flippantly noting that "Nazi ’hunters’ are on the loose again."

ICE now houses the evidence of the INS’ failures, and it too isn’t cooperative on the subject of war criminals. It has been extremely reluctant to release its files through the Freedom of Information Act, and when it does, it routinely applies unwarranted redactions to their contents, demonstrating a higher concern for the privacy of deceased accused war criminals than for transparency about the agency’s history.

The next time you hear about ICE agents hauling away a hard-working, law-abiding immigrant, put the incident in the context of the same institution’s history of allowing Nazis, and their accomplices, a safe haven in the United States. Like Mykola Kowalchuk, Edwin Marcial is a "hard-working" member of his community — but he isn’t white and he didn’t participate in war crimes.

Jared McBride is a lecturer in the history department at UCLA. He is at work on a book about war crimes prosecution during the Cold War.