It was 8 a.m. on a Saturday last June, and Angelica Vargas was folding laundry while her girls ate breakfast at home in Downey, California. Her 15 and 16-year-old daughters, both student athletes, didn’t have any soccer games scheduled that day, and her graveyard shift at a youth shelter didn’t start until 11 p.m. Vargas, 34, had nowhere to be—just “one of those days where you catch up on all your stuff,” she tells me on a video call in March. In single-mother terms, it was a unicorn morning. Then her phone rang. It was Vargas’ mother, her voice measured, calling to tell her that her older sister was at the Home Depot in Paramount when border patrol agents had swarmed the store. Her sister, who had simply been shopping, was trapped in the parking lot while people around her were being tear-gassed and grabbed without explanation. Vargas’ first instinct was disbelief. “I thought she was exaggerating because that's just my sister ," she says. “She’s 10 years older than me, but she’s a big baby.…