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Press Release

Brooklyn Man Sentenced In Manhattan Federal Court To 20 Years In Prison For Attempting To Provide Material Support To ISIS

For Immediate Release
U.S. Attorney's Office, Southern District of New York
Zachary Clark Disseminated ISIS Propaganda and Bomb-Making Instructions in an Effort to Incite Acts of Terrorism and Violence in New York City and Elsewhere

Audrey Strauss, the United States Attorney for the Southern District of New York, John C. Demers, Assistant Attorney General for National Security, William F. Sweeney Jr., the Assistant Director-in-Charge of the New York Field Office of the Federal Bureau of Investigation (“FBI”), and Dermot Shea, the Commissioner of the Police Department for the City of New York (“NYPD”), announced that ZACHARY CLARK, a/k/a “Umar Kabir,” a/k/a “Umar Shishani,” a/k/a “Abu Talha,” was sentenced today to 20 years in prison, for attempting to provide material support to the Islamic State of Iraq and al-Sham (“ISIS”).  CLARK pled guilty on August 10, 2020, in Manhattan federal court before U.S. District Judge Naomi Reice Buchwald, who sentenced Clark today.

U.S. Attorney Audrey Strauss said:  “Zachary Clark pledged allegiance to ISIS and posted calls for attacks on the public and institutions in New York City on encrypted pro-ISIS chatrooms, along with detailed instructions for carrying out those violent acts.  Thanks to the Joint Terrorism Task Force, Clark’s efforts to incite deadly violence on behalf of ISIS have been silenced.  Today’s sentence sends a clear message that those who seek to further ISIS’s campaign of terror and violence, no matter the method, will face serious consequences.”

Assistant Attorney General John C. Demers said:  “Today’s 20-year sentence recognizes the gravity of Clark’s conduct, including his calls for other ISIS supporters to carry out lone wolf terrorist attacks in New York City. Having pledged allegiance to ISIS, Clark provided others with specific instructions on knifing and bomb-making for use in such attacks. We remain vigilant to the threat of terrorism and committed to identifying and holding accountable those who threaten our communities through their support for foreign terrorist organizations.”

FBI Assistant Director William F. Sweeney Jr. said:  “Zachary Clark will no longer spend his time in chat rooms supporting terrorist ideals, but behind bars in federal prison for the next 20 years. The successful ending in this case is a result of the dedication of the FBI’s JTTF here in New York and our partners around the world. We will continue to work together to protect the people of New York from anyone who wishes to do us harm.”

NYPD Commissioner Dermot Shea said:  “Zachary Clark, using encrypted social media platforms became the facilitator for the voice of ISIS in America. He controlled a private channel, communicating with ISIS followers, posting terrorist attack manuals and bomb making instructions and making statements in support of suicide attacks. He also affirmed his own ambitions of becoming a martyr for ISIS on US soil. His arrest comes out of the tight-knit partnership of the Joint Terrorism Task force agents and detectives as well as the NYPD’s Intelligence Bureau. It is another example---among many---of protecting New York City from terrorist violence through intelligence sharing, joint investigation, and prosecution, which results in prevention.”

According to the Indictment, Complaint, other court filings, and statements made during court proceedings:

CLARK pledged allegiance to ISIS twice, first in July 2019, to ISIS’s then-leader Abu Bakr al-Baghdadi, and then in October 2019, to ISIS’s new leader, Abu Ibrahim al-Sashemi al-Qurayshi, whom ISIS promoted after al-Baghdadi’s death.  Beginning in at least March 2019, CLARK disseminated ISIS propaganda through, among other avenues, encrypted chatrooms intended for members, associates, supporters, and potential recruits of ISIS.  CLARK’s propaganda included, among other things, calls for ISIS supporters to commit lone wolf attacks in New York City.  For example, on August 3, 2019, CLARK posted instructions about how to conduct such an attack, including directions on how to select an attack target, how to conduct preoperational surveillance, how to conduct operational planning, and how to avoid attracting law enforcement attention when preparing for and conducting the attack.  On another occasion, CLARK posted a manual entitled “Knife Attacks,” which stated, among other things, that discomfort at “the thought of plunging a sharp object into another person’s flesh” is “never an excuse for abandoning jihad” and that “[k]nives, though certainly not the only weapon for inflicting harm upon the kuffar [non-believers], are widely available in every land and thus readily accessible.”  CLARK urged the participants in encrypted chatrooms to attack specific targets, posting maps and images of the New York City subway system and encouraging ISIS supporters to attack those locations.  CLARK’s guidance also included posting a manual entitled “Make a bomb in the kitchen of your Mom,” which was issued by al-Qaeda in the Arabian Peninsula and included detailed instructions about constructing bombs using readily available materials.    

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In addition to his prison sentence, CLARK, 42, of Brooklyn, New York, was sentenced to lifetime supervised release.  

Ms. Strauss praised the outstanding efforts of the FBI’s New York Joint Terrorism Task Force, which consists of investigators and analysts from the FBI, the NYPD, and over 50 other federal, state, and local agencies.  Ms. Strauss also thanked the Counterterrorism Section of the Department of Justice’s National Security Division.

This prosecution is being handled by the Office’s Terrorism and International Narcotics Unit.  Assistant U.S. Attorneys Gillian Grossman, Matthew Hellman, and Sidhardha Kamaraju are in charge of the prosecution, with assistance from Trial Attorneys Jason Denney, Justin Sher, and Chad Davis of the National Security Division’s Counterterrorism Section.


Nicholas Biase, Jim Margolin
(212) 637-2600

Updated May 12, 2021

Press Release Number: 21-114