The shooting at Walmart yesterday is suspected to have been motivated by anti-immigrant sentiments. El Paso is located on the border between the U.S. and Mexico, and this particular store is, according to The New York Times, located just 10 minutes from the Bridge of the Americas, which connects El Paso to its Mexican sister city, Ciudad Juarez. Of the 20 people killed, six were Mexican citizens; the Times notes that the Walmart is known to be “a regular destination for Mexican tourists who come to the city to shop and visit family.” Just minutes before the shooter opened fire on Saturday, a long manifesto about a “Hispanic invasion of Texas” appeared on the forum site 8chan, and authorities are investigating whether the suspect—a 21-year-old white man from Allen, Texas, some nine hours from El Paso—authored it.

Read: White nationalism’s deep American roots

Whether or not the suspect wrote the manifesto, its existence and the atrocities committed yesterday, even taken separately, illustrate a grim reality: Immigrants to the U.S. from Latin America regularly face discrimination, hatred, and violence—especially at a moment in history when the president himself promotes anti-immigrant and white-nationalist rhetoric.

The hardship is compounded for undocumented immigrants, who often live their daily lives under an ever-present cloud of stress and logistical obstacles. As Sarah Elizabeth Richards wrote for The Atlantic in 2017, the looming threat of deportation in the United States nowadays has had negative effects on the physical and mental health of undocumented immigrants and their loved ones. And as Joanna Dreby, an associate professor of sociology at the University at Albany SUNY who researches immigration and its effects on families and children, points out, mixed-status families are so common in America today that the threat of deportation for any one undocumented immigrant can be a source of stress, anxiety, and depression for a surprising number of other people who are under no such threat themselves. “I’ve mostly done work with kids, most of whom are U.S. citizens,” Dreby told me. “They’re not undocumented, but they carry around these fears, these anxieties related to their parents or family members’ status.”

Times of crisis are when undocumented immigrants and their families find themselves particularly vulnerable. Immigrant communities are remarkably resourceful, Dreby said; they’re good at forming what sociologists call “informal social-support networks,” which can be great for finding jobs, friends, or child care. “But in a crisis situation, informal social support doesn’t do very much,” she added. When more formal support is required—when people need legal or medical aid, or assistance locating family members or getting treatment after a mass shooting, as has been the case in El Paso—undocumented people are often forced to choose between seeking help from institutions that might put them at risk of deportation or simply going without the care or help they need.