A recent article in the Guardian described an “off-the-books interrogation compound” where Chicago police secretly hold criminal suspects for questioning for hours on end, beyond the reach of lawyers, family members, and basic constitutional protections.

“I had been looking for him for six to eight hours, and every [police official] I talked to said they had never heard of him,” one Chicago attorney says of a client, who, like other detainees at the nondescript warehouse on the city’s west side, was kept out of official booking databases.

People are rightly shocked to learn that police in the US have allegedly been “disappearing” criminal suspects and subjecting them to ill-treatment. But it bears pointing out that in the parallel legal universe that is the U.S. immigration system, hundreds of thousands of people are routinely held in detention facilities under similar circumstances — for days, weeks, even months at a time — while they await court hearings or deportation for civil immigration violations.

Family members and lawyers of immigrant detainees often have a tough time finding them. Immigration and Customs Enforcement (ICE), which has custody over immigrants caught in the interior of the US, often doesn’t enter names into its online detainee locator system until at least 72 hours after they have been taken into custody, and sometimes longer. And that’s assuming ICE spells their names correctly in its database,which is not always the case. US Customs and Border Protection (CBP), which has authority over immigrants caught within 100 miles of US borders, doesn’t provide a locator service at all for the individuals detained in at least 130 small substations dotting the border.

During the 14 years I’ve been investigating rights abuses in U.S. immigration detention for Human Rights Watch, I’ve often heard about the problems relatives and attorneys face in locating detainees. One lawyer told me, “I have taken calls from seriously hysterical family members — incredibly traumatized people — sobbing on the phone, crying out, ‘I don’t know where my son or husband is!’”

It can be equally challenging for immigration detainees to contact the outside world. Those in the southwest border region have told us that the ability to make a phone call from CBP detention is often up to the discretion of the Border Patrol officer in charge. Even for detainees who get permission, they need money to purchase a phone card, and calling is very expensive – as much as $13 for a single 15-minute call. For those without that kind of money, the only option is a collect call. But phone lines in detention centers, like many lines these days, are often set up to block collect calls, and until family members figure out they need to remove those blocks, hours and days can go by.

And the ability of family members to locate a loved one is not all that’s at stake. Often, the only chance immigrants have to defend against deportation is to have family members in close touch, helping from the outside to search for a lawyer and compile evidence needed for their cases.

Basic rights taken for granted in the criminal justice system are withheld from immigration detainees — by law. Immigrants facing deportation have no legal right to a court-appointed attorney, and in fact some 83 percent go through the entire process without counsel. This can involve several hearings, sometimes over videoconference, with a government prosecutor arguing for deportation before a judge and no one but the immigrant disputing the government’s case. Nor is there any requirement that the arrest of an immigrant detainee be based on “probable cause,” as in the criminal context. Instead, the government asserts that it can detain immigrants while it investigates their legal status.

Even if a detainee is located, there’s always a risk that he or she will disappear again with little or no notice in the sprawling network of more than 200 immigration detention facilities nationwide. In two investigations, in 2009 and 2011, I detailed how ICE has built a detention system, relying on subcontracts with state jails and prisons, that functions by shuffling detainees among facilities. As a result, most detainees at some point during their detention will be transferred by government-contracted car, bus, or airplane from one detention center to another: 52 percent of detainees experienced at least one such transfer in 2009, in some cases from one side of the country to the other. Such long-distance transfers have dire consequences for immigrants’ rights to fair immigration proceedings, rendering attorney-client relationships unworkable and separating immigrants from the evidence they need to present in court, not to mention making family visits so costly that they rarely — if ever — occur.

It’s true that there have been some improvements in the past few years. In 2012, ICE announced new rules intended to reduce the number of detainee transfers. And, a recent Federal Communications Commission ruling set some rate caps on interstate calls from jails and prisons, including those where immigrants are often detained. Nevertheless, it is unclear how much the ICE reforms have actually reduced transfers, and phone calls within a state aren’t covered by the FCC’s ruling. Immigrants are still disappearing into immigration detention on a daily basis, remaining out of contact for periods of time that dwarf the six to 20 hours of secret detention the Chicago criminal suspects were subjected to.

The same day I read about the Chicago facility, I had been going through some mail, which included seven letters from detained immigrants. I wondered, “if I didn’t have these letters, if all I knew was that my immigrant relative went to work one morning and never came back, would I be able to find him?” I started typing the names on the envelopes into ICE’s detainee locator system. I found five. But two men from El Salvador had written letters from detention centers in California postmarked November 2014 and January 2015. When I entered their names into the system, both came up with “zero matching records.”

It’s possible that these immigrants were already deported. But ICE claims it keeps names in its system for 60 days past release or deportation. In any case, I knew that if one of them had been my son or my husband, I would have no way of finding him. Unless I had a different name or spelling for his name than what was on those envelopes, I would be at my wits’ end, wondering about his safety, if he was held nearby, moved somewhere far away, or already deported. I would be terrified.

Alison Parker is co-director of the U.S. program of Human Rights Watch.