The fear among immigrants was exacerbated by a case in El Paso, where Immigration and Customs Enforcement agents arrested a woman in February moments after she received a protective order against the man she said had abused her. The United States Commission on Civil Rights, a bipartisan independent agency, urged federal officials this past week to reconsider their courthouse arrest tactics. The agency said the Texas case and other courthouse arrests were having a chilling effect on immigrants throughout the country.

The Department of Justice declined to comment on the concerns about increased fear among immigrants.

Laura’s House, which helps hundreds of victims of domestic violence in Orange County each year, routinely asks clients about their immigration status so it can help them apply for visa protections if necessary. Under what is known as a U visa, victims of certain crimes receive permission to stay in the United State if they assist the police — and the promise of the visa often persuades victims of sexual assault and domestic violence to come forward.

Previously, nearly half of the more than 70 new cases that Laura’s House received each month came from undocumented immigrants. In the last three months, that number has dropped to less than one a week.

Many women share the concerns of April, 23, who waited for years before pressing charges against the father of her children and who asked that her full name not be used.

“I would call the police and use another name or make a neighbor call,” said April, who came across the border from Mexico when she was about 8 and lives in Orange County. “When he came after me, he’d say that I would get sent back to Mexico and never see my kids again. I believed him for a long time.”

Capt. James Humphries, who oversees the special victims investigations division in Montgomery County, Md., said he saw the willingness to report drastically backsliding in the county, where immigrants make up a large portion of the population. His unit has received roughly half the calls for sexual assault and domestic violence this year that it did in the same period last year, he said.