On any given day, the Cook County Jail holds hundreds of inmates picked up on criminal charges who also happen to be wanted for an immigration violation. Sheriff Tom Dart’s office keeps them up to 48 hours beyond when the criminal cases would allow them out. That’s to allow Immigration and Customs Enforcement, the federal agency known as ICE, to take them into deportation proceedings. Now Dart tells WBEZ he’s reconsidering that policy because it could be compromising public safety. We report from our West Side bureau.

SOUND: Keys open a jail door.

Beneath the Cook County criminal courthouse, one jailer pulls out keys and unlocks a door. Another, Officer Carmelo Santiago, leads the way.

SANTIAGO: We’re going through this tunnel that connects us from the courthouse to the jail. This way is where the detainee is going to be coming.

We step around crusts of sandwiches that the day’s new arrivals got for lunch.

SANTIAGO: And this is the receiving process.

SOUND: Entering the receiving area.

The smell of unwashed feet wafts from chain-link pens full of inmates who’re waiting to be processed. Santiago shows me the paperwork of a Mexican national busted last night in Chicago.

SANTIAGO: This individual was arrested for driving on a revoked or suspended license on a DUI.

A lot of immigrants who drink and drive end up in this jail. That’s because Illinois considers DUI a felony when the motorist lacks a valid driver’s license. And the state doesn’t allow any undocumented immigrant to get one.

SANTIAGO: He was issued a bond from the court for $15,000.

Santiago points out that the defendant could walk free for just $1,500. Except, his file shows something else.

SANTIAGO: This specific individual has a detainer that was placed on him through immigration.

MITCHELL: This man can post bond or not [and] he’s going to end up in the custody of Immigration and Customs Enforcement?

SANTIAGO: That is correct.

Cook County Sheriff Tom Dart says he doesn’t like holding on to inmates like this one for ICE to take away. He says these holds make it harder for local police to fight crime. Residents see cops and start thinking about the threat of deportation — the threat to the criminals, maybe even to themselves.

DART: It does not lend itself to a sense of community where people will gladly come to you with information about crimes, get involved as a witness, even come forward as a victim, frankly.

Over the years Dart has taken steps to reduce the jail’s role in immigration enforcement. The sheriff’s office says it no longer calls ICE with information about inmates. The sheriff no longer allows ICE agents in holding cells near bond courtrooms. The jail has put up big signs — in English, Spanish and Polish — that tell new inmates they have no obligation to answer questions about immigration status. But Dart says something has him in a bind. Every day ICE requests that the jail hold certain inmates two extra days so the agency can put the detainees into deportation proceedings. The jail ends up turning over about a half-dozen inmates to ICE each day. Two years ago, Dart quietly sought some legal advice from Cook County State’s Attorney Anita Alvarez’s office.

DART: The opinion was really unambiguous. It said I had to comply with the detainer. So, when the detainer was placed on somebody, I had to give the ICE officers 48 hours to come and pick somebody up and that it was not in my discretion.

MITCHELL: Could you ignore the state’s attorney’s opinion?

DART: Then I open myself up personally to civil liability.

Dart says that could include damages for someone hurt by a released inmate or the legal defense if an anti-immigrant group filed suit …

DART: … which is not something that myself or my five children signed up to do. And I open our office up to unbelievable amounts of liability.

But some immigrant advocates are pressing Dart about the ICE detainers. They confronted a few of his top aides at a meeting a few weeks ago. Reverend Walter Coleman got to question a sheriff’s attorney, Patricia Horne.

HORNE: It’s a legal document just like an arrest warrant, which we, under law, have to recognize.

COLEMAN: Under what law?

HORNE: Well, in this case, under federal law.

COLEMAN: There is no federal law. You cannot cite me the statute or the chapter or the section. You know that that’s the truth and we will not sit here and be lied to like this.

It turns out ICE isn’t citing a statute either. Lately federal officials have acknowledged that local jails don’t have to comply with immigration detainer requests. Last month the San Francisco County Sheriff’s Department quit honoring the requests for certain inmates. Here in Cook County, Sheriff Dart says that’s got him wondering again whether he has to comply with the 48-hour holds. He tells me he’s planning to ask the State’s Attorney’s Office for an updated opinion. He could do that quietly again and most people wouldn’t even know. But Dart doesn’t always operate quietly. You might remember that, twice over the last three years, the sheriff has ordered his deputies to suspend enforcement of foreclosure evictions.

MITCHELL: You run one of the country’s biggest jails. Would you really be willing to become a national lightening rod on the issue of immigration enforcement?

DART: Well, there is this notion of justice that we’ve always felt very strongly about in this office. And whether it’s dealing with people who we felt were being dispossessed of their houses in the mortgage crisis. So we stopped. It’s the same issue here, where we are attempting to do what is right and just.

But Immigration and Customs Enforcement spokesman Greg Palmore has a warning for any sheriff who lets inmates walk free despite an immigration hold.

PALMORE: Though ICE has not sought to compel compliance through legal proceedings, jurisdictions who ignore detainers bear the risk of allowing that individual back into the public domain before they were thoroughly vetted to insure that this individual doesn’t have anything outstanding that warrants us to move further in that particular case.

Sheriff Dart acknowledges there could be a downside to ignoring immigration detainer requests. Let’s say ICE knows the inmate arrived in the country under an alias or is violent — and the information didn’t appear in the jail’s background check. But Dart says letting some immigrants out of jail even though ICE wants them could be worth the risk. It might help remove the deportation issue from everyday policing. The sheriff says that could make streets in Cook County safer.