Man who caused shutdown at Chicago's federal courthouse pleads guilty, faces 2 years in prison

The man who caused the lockdown, evacuation and hourslong standoff at the Dirksen Federal Courthouse last year pleaded guilty Thursday to possessing a dangerous weapon in a federal court facility and now faces up to two years in prison.

U.S. District Judge Mary Rowland set Mario Santoyo’s sentencing for Jan. 12. Santoyo admitted to the judge that he’d carried a knife with a blade longer than 2 ½ inches into Chicago’s federal courthouse in July 2025.

When a prosecutor briefly recounted the allegations against Santoyo, Rowland asked whether they were accurate.

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Standoff at Dirksen Federal Courthouse with knife-wielding man ends after 9 hours

“That’s factual,” Santoyo told the judge.

Santoyo, 40, also wore a backpack the day of the courthouse lockdown. Authorities “had no idea” what was in it, his attorney has acknowledged.

The resulting standoff lasted roughly nine hours, shut down traffic on South Dearborn Street and eventually prompted an evacuation of the 30-story downtown tower.

Though Santoyo pleaded guilty to a crime that carries a maximum sentence of two years in prison, federal guidelines call for a sentence of no more than six months behind bars, authorities estimated Thursday.

When Santoyo arrived at the courthouse at 219 S. Dearborn around 10:30 a.m. on July 22, 2025, he asked for the FBI and claimed that “gangsters” or "gangbanners" were trying to kill him, according to a criminal complaint.

After a court security officer told him the FBI’s offices were elsewhere and asked him to leave, Santoyo pulled out a knife, held it to his throat and said he was going to hurt himself, records show.

Occupants of the building in the floors above were notified by loudspeaker of the incident — and they were told to avoid the lobby. Authorities cleared Federal Plaza across the street, traffic on South Dearborn stopped flowing and a drone began to hover near the courthouse entrance.

Later, around 2 p.m., court officials told people in the building’s second-floor cafeteria how to safely exit the building. A short time later, they declared the evacuation mandatory. Officials led people through exits on the east side of the lobby, and then toward State Street.

Law enforcement officials could also be seen searching a silver Chevrolet Impala parked near West Jackson Street and South Dearborn.

It wasn’t until nearly 8 p.m. that law enforcement “used non-lethal force” and took Santoyo into custody, records show. He dropped the knife he’d been holding but turned out to be carrying a second blade, according to the feds.