Something just felt off. The FBI was holding a press conference about a terrorist bust. But weirdly, the bust had gone down in Miami’s Liberty City, a largely African-American and Haitian-American neighborhood with high crime rates, a heavy police presence and few links to countries known for Islamic terrorism. Didn’t seem like the sneakiest locale for a terrorist cell, journalist Trevor Aaronson thought.

So Aaronson started digging. And digging. And digging. Gradually, he unearthed what looked like a trend: a string of alleged terrorists with few or no ties abroad. That perplexed him too. During a fellowship with the UC Berkeley Investigative Reporting Program, Aaronson combed through records of more than 500 domestic terrorism prosecutions and eventually found the entity that, he says, backs more terrorism plots on U.S. soil than al-Qaeda, al-Shabab and ISIS combined. It was the FBI.

It sounds like something out of a thriller spy movie. In Aaronson’s reconstruction, the FBI created a web of 15,000-plus informants, many of them ex-cons or con men, and paid them as much as “six figures to spy on communities in the United States.” The informants would target Muslim-Americans, many of them with mental-health problems, at mosques or on social media. Then the informants would convince the men to plot to shoot up community centers or plant car bombs, often providing fake weaponry. Then, when the “terrorists” went to act on their plans, the FBI would come in, guns blazing, and lock the men behind bars. In Aaronson’s words: “They’re creating terrorists to catch them.”

The FBI’s Miami field office declined our request for comment; a spokesperson at the bureau’s national headquarters directed us to material on the FBI website regarding the use of confidential informants, which points out that the practice is lawful and may involve “an element of deception, intrusion into the privacy of individuals, or cooperation with persons whose reliability and motivation may be open to question.” Aaronson, who published his findings in a book as well as outlets like The Intercept, says the FBI did not comment on or deny his findings.

Those findings suggest that the bureau has assembled a network 10 times larger than notorious former FBI director J. Edgar Hoover’s domestic spy network. Of the 508 cases in Aaronson’s database, only a handful had dangerous overseas links to al-Qaeda or ISIS. And countless of the soon-to-be terrorists suffered from severe mental illness, like schizoaffective disorder, which means they have trouble distinguishing between truth and fantasy. One man had done 12 stays in psychiatric hospitals, Aaronson wrote. He also received transcripts of recordings of FBI agents in Tampa openly mocking the terrorists in the making, calling one a “retarded fool” and acknowledging that they were in it more for money than religious fervor. A judge buried those transcripts in the name of national security, Aaronson says.

His work is a major contribution to what we know about how the FBI operates at a time when the nexus between government surveillance and civil liberties is, in his words, “the story of our generation.” Sharon Rosenhause, board president of the Florida Center for Investigative Reporting, says the topic is rarely covered in a “sophisticated, ongoing way.” She describes Aaronson, who is the FCIR’s co-founder and executive director, as “formidable” and “very intense.”

The informants Aaronson has covered are far from likable. At the same time, they are often blackmailed into cooperating with the government, whether they’re facing criminal charges the FBI promises to drop, are in desperate need of cash or are about to be deported, something the FBI can wave away. While Aaronson’s investigations have led to a book, The Terror Factory: Inside the FBI’s Manufactured War on Terrorism, and provided material or inspiration for documentaries, there have been no congressional hearings or major changes in the practices, he says. Apathy remains a challenge. No one — especially the Muslim-Americans affected most — wants to be seen as defending terrorism-related anything, he says.

And not everyone thinks his work is great. Critics call him a terrorist apologist; it doesn’t help that al-Qaeda’s slick magazine, Inspire, once included a photo of him plastered with quotations the terrorist organization interpreted as supportive. But he brushes away such criticisms, with a surprisingly distant nonchalance, as a product of widespread Islamophobia and a pervasive with-us-or-against-us mentality.

Instead, he offers a warning: “Anytime the government has a toy or tactic, it starts with a vulnerable population,” he says. If Aaronson keeps up his current work, maybe he’ll report out other yet-undiscovered happenings and add another award to the two dozen he’s already received.