E VAN KOHLMANN IS the U.S. government’s go-to expert witness in terrorism prosecutions. Since 2004, Kohlmann has been asked to testify as an expert about terrorist organizations, radicalization and homegrown threats in more than 30 trials. It’s well-paying work — as much as $400 per hour. In all, the U.S. government has paid Kohlmann and his company at least $1.4 million for testifying in trials around the country, assisting with FBI investigations and consulting with agencies ranging from the Defense Department to the Internal Revenue Service. He has also received another benefit, Uncle Sam’s mark of credibility, which has allowed him to work for NBC News and its cable sibling, MSNBC, for more than a decade as an on-air “terrorism analyst.” Kohlmann’s claimed expertise is his ability to explore the dark corners of the Internet — the so-called deep web, which isn’t indexed by commercial search engines — and monitor what the Islamic State, al Qaeda and their sympathizers are saying, as well as network the relationships among these various actors. Kohlmann doesn’t speak Arabic, however, and aside from a few days each in Saudi Arabia, Jordan, Dubai and Qatar, has hardly any experience in the Arab world. Kohlmann’s research is gleaned primarily from the Internet. Indeed, Kohlmann is not a traditional expert. Much of his research is not peer-reviewed. Kohlmann’s key theory, to which he has testified several times on the witness stand, involves a series of indicators that he claims determine whether someone is likely a homegrown terrorist. Yet he has never tested the theory against a randomly selected control group to account for bias or coincidence. For these and other reasons, Kohlmann’s critics describe him as a huckster.

Kohlmann’s works are “so biased, one-sided and contextually inaccurate that they do not provide a fair and balanced context for the specific evidence to be presented at a legal hearing,” said one terrorism researcher.

In a court filing, Marc Sageman, a forensic psychiatrist and former CIA officer who has been called to the witness stand several times to discredit Kohlmann’s claims, described his testimony and reports as “so biased, one-sided and contextually inaccurate that they do not provide a fair and balanced context for the specific evidence to be presented at a legal hearing.” In recent months, however, the small cohort of defense lawyers nationwide who battle the government in terrorism prosecutions have been asking themselves another question: What’s in the government’s mysteriously classified materials about Kohlmann? The question began circulating last year. While representing at trial Mustafa Kamel Mustafa, of the Finsbury Park Mosque in London, New York lawyer Joshua Dratel, who has security clearances, was given classified materials about Kohlmann, a witness in the Mustafa prosecution. “It was the integrity of a prosecutor who learned of [the materials] some way,” Dratel said, crediting a single Justice Department employee for providing a rare full disclosure about Kohlmann. Dratel has reviewed the classified materials in full, but he is prohibited from discussing their contents publicly. “It’s hard to talk about it without talking about it,” he said. However, the judge in the Mustafa case allowed very limited references to the contents of the classified materials during Dratel’s cross-examination of Kohlmann — providing a clue to what the government is hiding about its star terrorism expert. “You have done more than consulting for the FBI, correct?” Dratel asked Kohlmann. “Correct,” Kohlmann said from the witness stand. “You have done more than act as an expert for the government, correct?” Dratel followed. “That’s correct, yes,” Kohlmann admitted. That’s as far as the judge would allow. Kohlmann and the Justice Department did not respond to repeated requests to comment for this story. Asked if he thinks the information about Kohlmann should be classified, Dratel commented: “I think it’s unjustifiably classified now. I think the rationale for its classification is more connected to litigation, to protecting Kohlmann as a witness.” K OHLMANN GREW UP in South Florida and attended Pine Crest School, a tony prep school with campuses in Fort Lauderdale and Boca Raton.

“I applied to college not really knowing what I wanted to do, but I spent summers in France — my father grew up there — and I was always interested in foreign affairs,” Kohlmann said in a 2006 profile in Penn Law Journal, titled “Terrorists Beware; Kohlmann is on the Case.” Kohlmann studied political science at Georgetown and later law at the University of Pennsylvania, though he never took the bar exam. His steeping in terrorism studies can be credited to Steven Emerson, who founded a nonprofit think tank, the Investigative Project on Terrorism, which a young Kohlmann joined in 1998. “I started obviously as an intern, but by the time I left the Investigative Project in 2003, I was a senior analyst,” Kohlmann said in court testimony. Prior to the 9/11 terrorist attacks, Emerson successfully portrayed himself as a credible terrorism expert, thanks in part to his 1994 documentary, Terrorists Among Us: Jihad in America, which aired on PBS Frontline. His work at the Investigative Project on Terrorism, which he founded shortly after the airing of Terrorists Among Us, helped fuel speculation linking University of South Florida professor Sami Al-Arian to the Palestinian Islamic Jihad, and the Holy Land Foundation to Hamas. In addition to Kohlmann’s, Emerson also helped launch the career of Rita Katz, who runs the SITE Intelligence Group. “The Investigative Project was a nonprofit enterprise seeking to collect and harvest information — difficult-to-find information about the recruitment, communications, and financing of particular international terrorist organizations,” Kohlmann said in court testimony. “Then taking this information, and both in its raw form and by distilling it into unclassified memorandums, congressional testimonies, and other documents, including media … we then provided this information to a variety of different people, including, again, everyone from policymakers in Washington, DC, law enforcement, other academics, media, you name it.” (In recent years, while Kohlmann and Katz have maintained close relationships with the U.S. government and news media, Emerson has seen his star fade due to two embarrassing Fox News appearances — one in 2013, when he claimed a U.S. government official told him that a Saudi national initially suspected in the Boston Marathon bombings was being deported on national security grounds, and another this year, when he said Birmingham, England, was “totally Muslim” and off limits to non-Muslims.) While at the Investigative Project on Terrorism, Kohlmann wrote what would become his book, Al-Qaida’s Jihad in Europe: The Afghan-Bosnian Network. He initially submitted the manuscript to the University of Pennsylvania Press, where Sageman, who would become a chief critic of Kohlmann’s work as a government expert, was asked to serve on a peer review panel. He recommended against publishing the book. Kohlmann found a publisher in the United Kingdom, Oxford International Publishers, which had no affiliation with the University of Oxford. (Kohlmann has been asked whether he has intentionally tilted his testimony to leave the impression that his book’s publisher was linked to the prestigious university. “I did not deliberately attempt to exaggerate my credentials,” Kohlmann said in court testimony last year, countering this question.) With his book and stint with the Investigative Project on Terrorism as credentials, Kohlmann became an expert witness for the Justice Department and a consultant for the FBI. An FBI agent described the baby-faced expert as “the Doogie Howser of Terrorism,” and a George Washington University law professor described Kohlmann to New York magazine as having been “grown hydroponically in the basement of the Bush Justice Department.” Among Kohlmann’s earliest cases was the 2006 prosecution of Yassin Aref and Mohammed Hossain in Albany, New York. It was the first FBI counterterrorism sting to use Shahed Hussain, an aggressive criminal-turned-informant who was involved in the investigations of the so-called Newburgh Four — a sting involving four defendants and a plot to bomb synagogues in the Bronx and attack a nearby airport — and of Khalifah al-Akili, a botched sting operation in Pittsburgh in which the FBI informants’ covers were blown. The Albany case was a convoluted one involving a loan between Hussain, the informant, and Hossain, a local businessman who owned a pizzeria and a few rental properties. Aref, a local imam originally from Iraq, was brought in to observe the loan transaction and terms in accordance with Islamic law. The government alleged that Hossain and Aref knew the money was connected to the importation of missiles — the informant used a code word for the missiles, chaudry, the government alleged — but defense lawyers for the two men maintained that they believed the arrangement was a loan, not money-laundering for terrorists. To support charges that the pair was involved in terrorism, the government used the transcript of a recording between Hossain, the pizzeria owner who was originally from Bangladesh, and the FBI informant. “We are members of Jamaat-e-Islami,” Hossain said in the recording. The government initially claimed that Jamaat-e-Islami, a political party in Bangladesh, was linked to terrorism through a proxy organization, Jamaat-ul-Mujahideen. Rohan Gunaratna, a terrorism scholar at the S. Rajaratnam School of International Studies in Singapore, was originally going to testify to this connection as an expert. But the government instead brought in Kohlmann. Kevin A. Luibrand, a lawyer for Hossain, challenged Kohlmann’s knowledge as an expert. “Can you name any of the major political parties in Bangladesh from the year 2000 to 2004?” Luibrand asked Kohlmann in a deposition. “Other than Jamaat-e-Islami?” Kohlmann asked. “Yes.” “That’s — I’m not familiar off the top of my head,” Kohlmann said. “Have you ever heard of an organization known as the Bangladesh National Party?” Luibrand followed. “Vaguely.” “Do you know what it is?” “I’m assuming it’s a political party, but again — the name vaguely sounds familiar but …” Kohlmann answered. “Do you know what, if anything, it stands for politically within Bangladesh?” Luibrand asked, cutting off Kohlmann’s answer. “Sorry, can’t tell ya,” Kohlmann said. The Bangladesh Nationalist Party, to which Luibrand was referring, is one of the two largest political parties in Bangladesh and allied with Jamaat-e-Islami. “You can’t tell me because you don’t know?” Luibrand asked Kohlmann in a follow-up question. “I don’t know off the top of my head,” Kohlmann said. Kohlmann also admitted in the deposition that he had never written about Jamaat-e-Islami of Bangladesh. Luibrand asked to have Kohlmann disqualified as an expert, arguing that Kohlmann was unable to demonstrate knowledge of the groups he was testifying about. A judge denied the request and allowed Kohlmann to testify. Aref and Hossain were convicted and sentenced to 15 years in prison.