SCOTT SIMON, HOST:
Police departments across the U.S. are using electronic databases to store intelligence on gang activity. These databases have been heralded by police as a crime fighting tool. But some activists in Chicago claim they do more harm than good. Immigrants in particular say the city's list is full of errors. And in some cases, they lead to deportations. From member station WBEZ, Odette Yousef reports.
ODETTE YOUSEF, BYLINE: Fifteen years ago, the Chicago Police Department started gathering information about gangs electronically. It was the next big thing at the time for police departments. The idea was to store gang intelligence in one centralized system.
MICHAEL MARTIN: It allows us to reduce violent crime, to identify the most active gangs and gang members.
YOUSEF: Michael Martin is with the Midwest Gang Investigators Association and teaches at the National Gang Center based in Florida. He says today, most U.S. law enforcement agencies use some sort of database to track gangs, and they help with analyzing trends and prosecuting cases.
MARTIN: But we have to do this stuff, right? We have to ensure that we're protecting people's rights when we're doing this. Otherwise, the community's not going to trust us.
YOUSEF: In Chicago, that trust is eroding. Over time, Chicago's list has grown to include almost 65,000 people that the police consider gang-affiliated. More than 95 percent are African-American or Latino. Young activists say that police are irresponsibly and disproportionately labeling young men of color as gang members. And the information is leading immigration agents to those who are undocumented. Luis Pedrote Salinas says this is exactly what happened to him seven years ago.
LUIS PEDROTE SALINAS: They arrested me for an unopened Bud Light beer can. And just because of that, they picked me up. Then I was getting deported.
YOUSEF: Pedrote is an undocumented man from Mexico. He says he was getting into his car in a neighborhood that Chicago police were targeting for gang activity. They stopped him and spotted the beer can in his car. They arrested him. The case was never prosecuted. But that arrest has had long-lasting effects for Pedrote.
SALINAS: He said that I self-testified to be a Latin King. But I didn't testify nothing.
YOUSEF: Pedrote says he's not in a gang. But in Chicago, there's no official process to get off the database. And for Pedrote, the most frustrating thing is that he thinks being on the list killed his eligibility for DACA, the Deferred Action for Childhood Arrivals policy that protects some migrants who are brought to the U.S. as children.
SALINAS: We knew they denied me because of the gang allegations.
YOUSEF: Pedrote is suing the Chicago Police Department. And because of that, it won't comment on his claims. But the department did recently make an extraordinary admission in a separate but similar case. It said that even though it had labeled another undocumented man a gang member, it had no evidence to back that up. That cleared the way for the man to apply for a visa that he hadn't been able to get because of the label. Despite this, Chicago Police Superintendent Eddie Johnson still largely considers the database reliable.
EDDIE JOHNSON: I think that, you know, any facet of life that we deal with - there may be errors.
YOUSEF: The department says in court filings that changes to the database would be unworkable. But Michael Martin says databases should regularly be purged of wrong information. Otherwise, people's civil rights might be violated, and departments could eventually be forced to dismantle their databases. Martin says that's what happened to Minnesota's statewide database several years ago. And more recently, the Portland, Ore., police department also discontinued its gang database over the same concerns. For NPR News, I'm Odette Yousef.