Robert Snell

The Detroit News

Detroit — An American Muslim who allegedly bought illegal grenades from an undercover FBI agent is an Islamic State supporter who fantasized about killing local Muslim religious leaders and a park ranger, according to federal court records unsealed Monday.

Interviews and court records, for the first time, portray Detroiter Sebastian Gregerson, aka Abdurrahman Bin Mikaayl, as a homegrown extremist who allegedly amassed an arsenal to carry out an attack while cheering mass killings in Paris and Orlando.

The allegations are contained in an FBI search warrant affidavit listing probable cause to search Gregerson’s home and car on July 31. Agents were looking for evidence Gregerson, 29, was providing material support to a foreign terrorist group.

FBI agents raided Gregerson’s home on the 8300 block of Schaefer Highway south of Joy Road after Gregerson allegedly bought five illegal grenades that same day from the undercover FBI agent.

The search yielded an arsenal of weapons, including seven rifles, two AK-47 assault rifles, a shotgun, handguns, thousands of rounds of ammunition, computer equipment and cellphones, according to a sealed search warrant inventory obtained by The Detroit News.

Part of Gregerson’s arsenal included tactical knives similar to those used in videos of Islamic State extremists beheading western hostages, according to the FBI.

Gregerson also owned an underground ammunition storage container, the FBI claimed.

Agents had permission from a federal judge to dig up Gregerson’s yard and use a metal detector in hopes of finding the buried container, according to the affidavit. It’s unclear whether a container was found.

It appears agents have not found evidence indicating that Gregerson was providing material support to a foreign terrorist organization. He has not been charged with a terrorism-related crime, but the investigation is ongoing. And there was no specific planned attack outlined in the court records.

Instead, Gregerson, who is being held without bond, faces up to 10 years in federal prison if convicted of unregistered possession of a destructive device and unlicensed receipt of explosive materials.

16-month FBI investigation

The affidavit further portrays Gregerson as a vocal Islamic State supporter who spoke of violence while being secretly recorded by an undercover FBI agent during a 16-month investigation.

In May, Gregerson and the undercover agent met at an area restaurant. A group of local Muslim religious leaders entered the restaurant.

“Gregerson recognized the men. He then proceeded to talk with (the agent) about committing violent acts against them. He described the scenario ‘like shooting fish in a barrel,’ ” according to the affidavit.

It is not uncommon for Islamic State extremists to talk about harming local Muslim religious leaders, said Seamus Hughes, deputy director of George Washington University’s Program on Extremism, who has followed the case and reviewed the court filings for The News.

“Individuals drawn to (the Islamic State) don’t see prominent American Muslim religious leaders as legitimate,” he said. “They see them as sellouts.”

In June, Gregerson met with the agent at a Dearborn park, according to court records.

Gregerson spotted what he believed was a park ranger and described a way to launch an ambush and attack.

“People like this, this isn’t even a challenge,” Gregerson allegedly said. “You know they talk about all these lone wolves and all this kind of stuff, you know, threats. Listen, if someone really wanted to do something that knew what they were doing, they could do something, and they could do a lot.”

The bulk of the search warrant affidavit is based on secretly recorded conversations made by the undercover FBI agent who Gregerson believed was an Islamic State supporter.

The conversations were dominated by Gregerson talking about the Islamic State and weapons, particularly grenades and grenade launchers, according to the affidavit.

“In addition, on several occasions, Gregerson expressed his interest in committing violent acts,” according to the FBI.

During one conversation in April, Gregerson referenced the June 2014 declaration by militant leader Abu Bakr al-Baghdadi proclaiming the establishment of the Islamic State.

“Gregerson told the (undercover agent) that he watched al-Baghdadi’s speech some five times that day and celebrated the event with associates,” according to the affidavit. “Gregerson stated: ‘We could not stop smiling.’ ”

“There is no more ambiguity about this case,” Hughes said. “He’s been a true believer for a few years.”

Praise for Orlando attack

During the investigation, the FBI said Gregerson also praised Islamic State-inspired extremists, including Omar Mateen, the American-born man who killed 49 people at a gay nightclub in Orlando in June.

Gregerson, a Target employee who converted to Islam after high school, called Mateen his “brother” and offered constructive criticism about how the Orlando shooter could have boosted the body count, according to court records.

“If he would have just kind of stayed in there and held them off for a few more hours ... we would’ve been talking about 75 (fatalities) ...” Gregerson told the undercover FBI agent during a recorded conversation on June 21. “Then maybe he could have waited for the cops to come inside and try to pick off a couple of them on the inside ...”

During the prolonged investigation, Gregerson repeatedly expressed his support for Islamic State extremists, court records allege. Gregerson frequently visited Islamic State websites and praised extremists’ violent methods, according to the FBI.

Gregerson said he wanted to move with his wife and four-year-old twin sons to Islamic State territory and “remain there permanently,” according to the search warrant affidavit.

Until Monday, the FBI and U.S. Attorney’s Office had refused to disclose any evidence linking Gregerson with Islamic State extremists.

The U.S. Attorney’s Office declined comment on Monday, but the FBI did issue a statement.

“As a pending investigative matter yet to be adjudicated, the FBI cannot comment on the Gregerson investigation,” said David Gelios, special agent in charge of the Detroit office. “That said, the FBI prioritizes the investigation of terrorist organizations and the homegrown violent extremists that they inspire. Terrorism is something that requires constant vigilance on the part of the public and routine coordination with all of our public and private partners.”

David Tholen, Gregerson’s court-appointed lawyer, could not be reached for comment Monday evening.

But Tholen said during a recent court hearing that Gregerson is a gun enthusiast, hunter and survivalist who has no criminal record. The firearms in question were bought legally, his lawyer added.

Raid yielded al-Awlaki CDs

During the raid of Gregerson’s home on July 31, agents also found several CDs marked “Anwar al-Awlaki,” the al-Qaida recruiter who met with Umar Farouk Abdulmutallab before the failed Christmas Day 2009 terror attack on a Detroit-bound plane, according to the sealed search warrant records. Al-Awlaki was killed in a drone strike in Yemen in 2011.

Gregerson claimed to have all of al-Awlaki’s lectures, which have been used to radicalize homegrown violent extremists, according to the FBI.

According to further court records, in November, after extremists killed 130 people in a series of suicide bombings and shootings in Paris, Gregerson supported the attacks on Facebook.

“Only a fool would believe they are untouchable and that just because you kill people a thousand miles away every day it will not affect you,” Gregerson allegedly wrote. “The world is at war, when one engages your enemy in their homeland your homeland is not exempt. Accept responsibility for your actions if you dont (sic) want war in your land dont (sic) bring it to someone else’s home.”

Emails sent from Gregerson’s account also praised Islamic State extremists in emails sent between February 2015 and March 18, 2016, according to the FBI.

He disseminated the Islamic State’s official English language magazine, Dabiq, court records allege.

“One of its aims is to recruit individuals from western countries to commit ‘lone wolf’ attacks,” the FBI alleged.

Meanwhile on Friday, Gregerson’s lawyer agreed not to publicly reveal the undercover FBI agent’s identity.

The agreement, revealed in a court filing, prohibits the lawyer from disclosing the agent’s cover name or secret audio and video recordings, text and emails exchanged between the agent and Gregerson during the investigation. The agent’s cover name cannot be revealed in any court filings or public hearings prior to trial.

rsnell@detnews.com

(313) 222-2486

Twitter: @robertsnellnews