Thousands of times each year, police officers checking the name of an individual stopped or detained against records in the nation's main criminal database have received an initial "hit" for an immigration violation that, upon further investigation, the Department of Homeland Security could not confirm. These "false positives" have likely caused wrongful detentions and diverted scarce police resources from local public safety priorities, finds a report to be released on Thursday by the Migration Policy Institute.
The study, based on government data, finds that from 2002 to 2004, when police queried names in the FBI's National Crime Information Center database, the officer received erroneous immigration hits in almost 9,000 cases. The rate of false positives was 42 percent overall, and some individual law enforcement agencies had error rates as high as 90 percent.
"The incredibly high number of false positives in the database means that police resources, which are always stretched thin, are being wasted on detaining immigrants and non-immigrants alike who haven't done anything wrong," said MPI President Demetrios Papademetriou.
The report, Blurring the Lines: A Profile of State and Local Police Enforcement of Immigration Law Using the National Crime Information Center Database, 2002-2004, uses data released by DHS in partial settlement of a Freedom of Information Act lawsuit. The report provides the first glimpse of how immigration data in the NCIC is being used, by which local law enforcement agencies, and against which immigrants.
Key report findings include:
"The data suggest that asking police untrained in immigration law to detain people based on bad records is of dubious law enforcement value," said report co-author Michael Wishnie. "This likely damages police credibility, increases their legal liability, and undermines public safety by discouraging immigrant victims and witnesses from cooperating with police."
The full report is available online.