Our listeners wrote us to ask: What are these groups doing with the addicts’ papers? If they’re really trying to keep those documents safe, as Cardona-Maguigad was told by a founder of Segunda Vida, then why would they keep the papers even after an addict leaves? Could they be selling these addicts’ identities on the black market?

It turns out, where Puerto Ricans are concerned, there’s added reason for suspicion. Puerto Ricans’ identities are especially valuable, because they’re U.S. citizens — with Social Security numbers — and Spanish names.

In a federal case against an alleged Puerto Rican identity trafficking ring, law enforcement agents found that a set that included a birth certificate and Social Security card could fetch up to $2,500 on the black market. With that, an undocumented immigrant from South or Central America could obtain work authorization, a line of credit or even a U.S. passport.

Related: Puerto Rico exports its drug addicts to Chicago

I started hanging out in the same Back-of-the-Yards neighborhood where Cardona-Maguigad found many addicts in her story. I thought, if I could just ask a few of them to share their Social Security numbers with me, we could find out what’s happening with their personal information. Most of the men I found refused to share that data. They told me they’d gotten their documents back when they left the treatment programs, and they didn’t have reason to suspect foul play.

But then I met Joel.

He can’t recall when he was sent to Chicago for treatment, but he, too, dropped out of rehab at Segunda Vida. Most mornings, I found him loafing around outside, making friendly chit-chat with other street characters. But he’s still very much lost in the haze of his heroin addiction.

“When you go back to this, you get totally lost,” he told me one day, speaking in Spanish. “I don’t even know what day it is.”

‘It appeared I was working in Alabama’

I’m not using Joel’s last name, to protect his identity. At 34, he said the only identification he carries is a photocopy of an Illinois state ID. Like others who went to Segunda Vida for treatment, he surrendered his documents to the people running the program. Confiscating identifying papers is common practice at these kinds of unofficial treatment facilities. When he left, he said he didn’t get his documents back. He tried, returning to the residence several times, but eventually he gave up.

Later, Joel learned that his identity was being used by someone else. He discovered it when he found that his unemployment benefits had been frozen.

“When I went to the unemployment office I was told that they had to stop payment because it appeared I was working in Alabama and I had additional income there,” he said.

Joel shared his Social Security number with me, and with it, I got a rundown of his earnings over the years. What I found were classic signs of identity theft.

First, Joel said he hasn’t held a steady job in years. He recalled working at a corrugated paper factory in Chicago and some brief stints canning jalapenos and olives. But his record shows continuous earnings for nearly a decade — roughly $30,000 a year since 2006. Plus, the earnings swing erratically. One year it’s as high as $52,000, and another, it’s less than $16,000. And a lot the work is with temporary staffing agencies and food processing companies — two industries known for hiring undocumented immigrants.

Because it looked suspicious, I took what I found to a man named George Rodriguez. Rodriguez described himself as a founder of Segunda Vida and a former addict himself. He denied that the program ever sold addicts’ identities, and said people always get their papers when they leave.

Clearly that was not the case with Joel. And soon I found that he’s not the only one in this situation. In fact, the next guy I met had an even wackier story.

‘My credit was ruined’

Juan, 40, was told that the rehab program that he went to “lost” his papers.

“They kept my papers, my Social Security card, my ID, my birth certificate, everything,” he said in Spanish.

Then last year, he tried to get a car loan. That’s when he got his first inkling that something was up with his personal information.

“They said no because my credit was ruined,” he said.

So I took Juan’s Social Security Number, too, and showed what I found to several experts. Here’s a snapshot:

“Wow. Well. I know they say America’s the Land of Opportunity, but, boy, has his income jumped since arriving on the mainland,” said William Kresse, a professor at Governors State University and an expert on identity theft, on seeing Juan’s incomes.

The first red flag Kresse identified was the year that Juan’s income jumped significantly.

“Suddenly in 2003, the year that he was brought to the Chicago area, it jumps to almost $30,000, and then almost $44,000. And, oh my goodness, $116,000, almost $168,000,” said Kresse. “Yeah, this is remarkable.”

There were even earnings during times that Juan was in jail for theft and residential burglary. His records paint a frenetic picture, of a guy processing beef in Washington state, removing snow in Illinois, working at a Wendy’s fast food restaurant and holding thirteen other jobs… all in a single year.

There are some things we can’t say for sure. We can’t say that Juan and Joel’s identities were sold by the drug rehab programs. We can’t say that everyone who’s gone to one of these programs is a victim of identity theft. We can’t even say for sure that Juan and Joel didn’t sell their identities themselves. I asked, and they both said they didn’t. But federal law enforcement officials have found that some Puerto Rican addicts do that for a bit of cash.

Related: Sheriff calls on feds to investigate Puerto Rican agencies that send addicts to Chicago

That said, Bill Kresse said there is still enough here to warrant further action.

“Definite red flags to show that there’s probable cause to go ahead with a further investigation, in fact a criminal investigation into this,” he said. “The numbers alone should justify a criminal investigation.”

Kresse wasn’t the only one to say this. We found lots of officials who said there’s enough here to warrant concern. A federal prosecutor. A former Chicago police officer. Two former FBI agents. Someone with the Social Security Administration. The Illinois Department of Human Services. They agree that if these treatment places are organized schemes to set up vulnerable drug addicts for identity theft, somebody should go after them.

But nobody agrees on who should look into it.

Illinois Attorney General Lisa Madigan’s office said it’s a matter for Chicago Police or the FBI. Chicago Police and the FBI said there’s nothing to investigate if victims don’t report a crime. Immigration and Customs Enforcement doesn’t talk about whether it’s investigating something. And the Social Security Administration said it lacks jurisdiction to investigate identity theft.

So we know we have something. We just don’t have anyone willing to investigate it.

Odette Yousef is a WBEZ reporter. Follow her @oyousef and @WBEZoutloud.