SPRINGFIELD, Ill. – 10/26/26 – A Quincy, Illinois, man was arrested on October 25, 2026, by federal authorities following the execution of a federal search warrant.
Matthew Unglesbee, 36, of Quincy was taken into custody based on a federal criminal complaint charging him with violations of Title 18, United States Code, Section 1038 (False Information and Hoaxes), and Title 18, United States Code, Section 876 (Mailing Threatening Communications). United States Magistrate Judge Douglas J. Quivey held an initial appearance on October 26, 2026, and scheduled a detention hearing for October 28, 2026, at 3 p.m. at the federal courthouse in Springfield, Illinois.
The complaint, which was unsealed on October 26, 2026, alleges that Unglesbee was involved in mailing letters containing unknown substances to congressional offices. Because the arrest is based on a complaint, further specific details regarding the underlying allegations are limited at this time. A criminal complaint is merely an accusation, and a defendant is presumed innocent unless and until proven guilty.
“The use of the mail to threaten others, including the mailing of threatening substances, will not be tolerated. These threats will be investigated and prosecuted to the full extent of the law. My office appreciates the resources dedicated by the FBI and our law enforcement partners to keep our citizens safe,” said U.S. Attorney Gregory M. Gilmore.
“Safeguarding the democratic processes that serve Central and Southern Illinois requires a constant focus on keeping our public institutions safe from intimidation,” said Ryan Presley, Special Agent in Charge of the FBI Springfield Field Office. “Mailing unknown substances to congressional offices creates fear and disrupts the public institutions vital to our democracy. We, along with our partners, will remain vigilant in identifying and holding accountable those whose actions threaten to intimidate public officials or disrupt our democratic systems.”
The case is being investigated by the Federal Bureau of Investigation’s Springfield Field Office’s Joint Terrorism Task Force, and the U.S. Attorney’s Office for the Central District of Illinois. Assistance in this investigation was provided by the FBI Chicago Field Office, United States Postal Inspection Service, Quincy Police Department, and Task Force Officers from the Illinois State Police, Illinois Secretary of State Police, Springfield Police Department, and the Amtrak Police Department’s Chicago Office.
