It started out as a crimefighting tool. But over the years, an FBI effort known as “geo-mapping” evolved into something more expansive — a method to track Muslim communities, without any suspicion of a crime being committed.

Last month, Danger Room revealed that the FBI was training its agents that religious Muslims tended to be “violent” and that Islamic charity is merely a “funding mechanism for combat.” In response, both the FBI and the Justice Department promised full reviews of their training materials. But the geo-mapping effort indicates that the FBI may have more than just a training problem: The suspicion of ordinary Muslims promoted in those lectures may be spilling over into its counterterrorism tactics.

Last week, the American Civil Liberties Union acquired some of the FBI geo-maps (.pdf), like the one pictured after the jump, through a Freedom of Information Act lawsuit. Although many of the maps are heavily redacted, they represent the first public confirmation that the FBI compiles maps of businesses, community centers and religious institutions in ethnic enclaves around the United States.

The ACLU — where, full disclosure, my wife works — blasted the mapping effort, and in an interview with the New York Times, FBI agent turned ACLU attorney Mike German tied the maps to the incendiary anti-Islam trainings first revealed by Danger Room. Agents who received the briefings might be “predisposed to treating everyone from a particular group as suspect,” German said.

In response, the FBI issued a nuanced defense of its geo-mapping efforts. While pledging that the FBI “joins the ACLU in opposing racial or ethnic discrimination,” an FBI statement said that “[j]ust as putting push pins on a map will allow a local police chief to see clearly where the highest crime areas are, combining data that is lawfully collected into one place allows connections to be identified that might otherwise go unnoticed.”