Roxana Santos with Sen. Ben Cardin (D-Md.) and two of her four children on April, 3, 2017. (CASA/Courtesy of CASA)

FIRST, ROXANA SANTOS was racially profiled by sheriff’s deputies in Frederick County, Md., who took it upon themselves to approach and question her in 2008 as she sat on a curb eating a sandwich outside the restaurant where she worked as a dishwasher. Then she was illegally arrested by the deputies. who, despite having no training in immigration law — the violation of which is a civil matter, not a criminal one — decided they were empowered to serve as deportation agents.

A federal appeals court, which ruled that her arrest and 45-day detention ran afoul of the Constitution, held the county government liable for damages.

Now, just as Ms. Santos’s lawsuit against the county was on the verge of resolution — with the likelihood of a payment to her by Frederick County — she has been detained again, this time by U.S. Immigration and Customs Enforcement, whose agents detained her during a routine check-in. The timing of the arrest has the unsavory appearance of one law enforcement agency colluding to spare another from the consequences of its misconduct.

Ms. Santos is an undocumented immigrant from El Salvador who, like most such immigrants, entered the United States more than a decade ago, fleeing what she said was domestic abuse. Three of her children, born in this country, are U.S. citizens; the fourth, who is 18, is a legal permanent resident. She was ordered to be deported when she failed to appear at an ICE facility as instructed — though the notice she was given was in English, which she didn’t understand.

The Santos case is a textbook example of a local law enforcement agency’s contempt for civil rights and a federal law enforcement agency’s misuse of resources. No one wants criminal immigrants in this country, and to hear immigration hawks tell it, there should be plenty of dangerous predators keeping deportation agents busy. As for the harassment of Ms. Santos, what a waste of time.

A year ago, U.S. District Court Judge Catherine C. Blake attested to Ms. Santos’s helpfulness in adjudicating her pending civil rights lawsuit and said the court “strongly urges” that ICE hold off on deporting her while her claim is litigated. Instead of heeding the court’s request, ICE detained her last week — days before she would have appeared in court for mediation in her suit. She remains held in a detention center on Maryland’s Eastern Shore, meaning no resolution in her suit is possible.

Now the judge has stepped in at least temporarily to block Ms. Santos’s deportation. Her lawyers suspect federal officials are trying to silence her. Whatever the outcome of the immigration proceedings against her, it would be an outrage if her civil rights suit were derailed short of resolution.