Asked why the memo stopped short of forbidding districts to request immigration-related documents, Mr. Burman said: "This was developed by our team of lawyers, and vetted and discussed and shared with the N.Y.C.L.U.'s counsel.
The judge, for instance, may assume that among the destroyed documents were citizen complaints — some that were racially charged and did not contain accusations of any criminal activity — that requested immigration patrols in spots where the sheriff's office later conducted patrols.
The federal data, which officials began reviewing a year ago at the request of immigration lawyers, offers the first public snapshot of the number of immigrants held in solitary confinement, how long they were there and how many had mental health problems — about 10 percent.
The new data, which federal authorities began reviewing a year ago at the request of immigration lawyers, looked at 50 detention centers over a five-month period that hold about 85 percent of the agency's average daily population of 34,000 detainees.
"I was shocked to learn in today's estimates that no border officials were made aware of my request, despite immigration officials admitting that I am within my rights to visit," she said.
Soon after this request, federal immigration officials issued a statement promising that undocumented workers who help the investigation as witnesses would not be slated for deportation and might even be eligible for special visa help.
Even gung-ho sheriffs have begun refusing to hold prisoners at the request of immigration authorities, ever since a federal district-court judge in Oregon ruled that a local sheriff was violating the constitutional rights of an immigrant woman by doing so.
"[REDACTED] then stated that when they were at the school, he and the other boys wrote a request to immigration and "if we don't get a response from them… we will go back to the school and jump off the roof".
