Editors’ note appended.

You get arrested. The authorities run a background check. They need to know if you have outstanding warrants or unpaid tickets, if you jumped bail somewhere, if you’re driving a stolen vehicle. To obtain your criminal history, they routinely send your fingerprints to the Federal Bureau of Investigation, which keeps a database of more than a hundred million prints. The F.B.I., under a federal program known as Secure Communities, will share your fingerprints with the Department of Homeland Security. Homeland Security’s core job—the reason it was created—is to prevent terrorist attacks on the United States. Your prints might reveal that you’re a suspected terrorist. D.H.S. is also charged with border security. Its Immigration and Customs Enforcement arm, ICE, will run your prints through the D.H.S. database—specifically, its U.S. Visitor and Immigrant Status Indicator Technology Program (U.S.-VISIT) and Automated Biometric Identification System (IDENT), which also contain more than a hundred million prints—searching for a match with people wanted for immigration violations. If a match occurs, ICE can issue a “detainer.” Now the local authorities, before they release you, may notify ICE, which may elect to transfer you to federal custody in order to begin deportation proceedings.

When Mark Lyttle, a U.S. citizen, was booked into Neuse Correctional Institution, a minimum-security state facility in Goldsboro, North Carolina, in August, 2008, much of the data exchanged between agencies, including the biometrics, appear to have been ignored. Lyttle, who is thirty-five, has had a difficult life. He was born in Rowan County, North Carolina, which is about two hundred miles west of Goldsboro, and he spent his early childhood in foster homes. He was adopted at the age of seven, along with two younger brothers and a sister, by Thomas and Jeanne Lyttle, who had one child of their own. Thomas Lyttle died a year later. Jeanne, an occupational-therapy assistant, reared five children. Mark is bipolar and diabetic. He has cognitive problems. He can read, but writes with difficulty. He has spent much of his time since adolescence in mental institutions, jails, and group homes. Before he went to Neuse, he was a patient at Cherry Hospital, a state psychiatric facility a few doors up the street. Earlier that year, he had been convicted of inappropriately touching a female employee at another facility. He was sentenced to a hundred days for misdemeanor assault.

This is a fair time to mention that the North Carolina director of prisons, J. Boyd Bennett, had, in 2007, signed an agreement that required facilities under his control, including Neuse, to coöperate with ICE enforcement agents by identifying inmates “believed to be foreign born and non-US citizens.” There are many types of overlapping agreements between local law enforcement and federal immigration authorities. Operation Secure Streets, one of Secure Communities’ pilot programs, was up and running in North Carolina by 2006. Secure Streets relied on raids to find deportable aliens. Secure Communities, like ICE’s agreement with J. Boyd Bennett, relies on combing the jails. This is not a new practice. ICE’s Criminal Alien Program, which also does “jail status check,” has been around, under one name or another, since 1988. In the past decade, however, deportations have soared, increasing every year since 2001. Last year, the United States deported more than four hundred thousand people—a new record.

Mark Lyttle’s intake form at Neuse contained some oddities and two fateful errors. The clerk typed in his full name, Mark Daniel Lyttle, twice, but labelled the second version, which is identical to the first, an “alias.” The clerk, after studying Lyttle, listed his “Race” as “Other.” For “Ethnicity,” the clerk went with “Oriental.” Lyttle’s birth date was recorded correctly, but the response he says that he gave to a question about his birthplace, “Rowan County, North Carolina,” was not. The spaces for Birth State, Birth County, and Primary Language were left blank. Then came the errors. Birth Country: Mexico. Citizenship: Alien. These incorrect entries flagged Lyttle for ICE’s Criminal Alien Program. His fingerprints, however, would presumably establish his U.S. citizenship—his criminal history, as kept by the F.B.I., shows his citizenship numerous times. That is one of the beauties of biometrics: its deployment can trump racial profiling.

The exact reasons for the Neuse intake clerk’s mistakes are unknown—the clerk’s identity is itself unknown—but the vagaries of race and ethnicity obviously played a part. Lyttle is brown-skinned. Had he been light-skinned, it’s unlikely that the clerk would have decided he was Mexican. Lyttle did not speak Spanish. His English was indelibly local. He told me, last year, that he believes his birth mother was white and his birth father was “mixed Puerto Rican and white.” Like many Americans, but with an extra dash of bafflement, perhaps, he has spent his life navigating a dense maze of racial attitudes, mostly in North Carolina, Virginia, and Florida. Every community carries its own worn racial baggage. Cherry Hospital, in Goldsboro, was once known as the Asylum for Colored Insane.

A few days after his arrival at Neuse, Lyttle was given a form, Non-Mandatory Consular Notification. It said that, as a non-U.S. citizen, he had the right to have his home country’s consulate notified of his status. He didn’t know quite what that meant.

He wanted to talk to his mother, to let his family know where he was. But he had lost the address book in which he kept their numbers. In fact, his mother had moved, temporarily, to Kentucky, where his brother Tommy was stationed as an Army staff sergeant. She was helping to look after Tommy’s son while he was deployed in Afghanistan.

ICE sent a deportation officer, Dashanta Faucette, from its Raleigh office to Goldsboro to interrogate Lyttle and roughly a dozen other Neuse inmates who had been flagged that week as possible illegal aliens. Faucette’s regular beat was federal lockups in North Carolina, but she was covering for a colleague who handled state facilities. Before interrogating Lyttle, she did not conduct a standard criminal-history check, which would have revealed his U.S. citizenship. Interrogating him, she concluded that “Mark Daniel Lyttle” was indeed an alias. Lyttle’s real name, Faucette’s notes showed, was Jose Thomas. He was born in Mexico and had been brought into the United States illegally at the age of three. Thomas was the first name of Lyttle’s deceased father. Otherwise, the new name appears to be pure fiction—possibly concocted by Lyttle himself, although that is not clear. When he was instructed by Faucette to sign a Record of Sworn Statement in Affidavit made out for Jose Thomas, he signed “Mark Lyttle.”

The interrogation had taken some weird turns. Lyttle wanted to know whether, if he was sent to Mexico, his girlfriend could come with him. And would he receive his mail there? He seemed to think that a trip to Mexico might be a kind of holiday, and that he would need his monthly disability checks. Faucette later insisted, in an affidavit, that she gave Lyttle every opportunity to assert his U.S. citizenship but he declined to do so. She noted, “I believe that he thought that he would get his jail time reduced by taking the immigration route.” Faucette assured Lyttle, incorrectly, that his mail could be forwarded to him, encouraging his fantasy of a Mexican vacation. In a box asking if the subject was eligible for any special-status program, Faucette wrote, “Mental Illness—Bipolar.” After his arrest for inappropriate touching, Lyttle had attempted suicide, by cutting himself. But his competence to represent himself was apparently never questioned by ICE. The right to counsel, guaranteed to criminal detainees under the Constitution, did not, in any case, extend to immigration detainees. In early September, ICE placed a detainer against Lyttle. Now he was on the deportation track.