CHICAGO (WLS) -- A standoff at the Dirksen Federal Building downtown Chicago ended after roughly nine hours Tuesday night.

The FBI and Chicago police are responding to a downtown federal courthouse for an "undisclosed incident" on Tuesday.

The FBI and Chicago police responded to a downtown federal courthouse for an "undisclosed incident" on Tuesday.

CBS News Chicago witnessed the man being tackled by law enforcement and removed from the courthouse lobby on a stretcher.

The Dirksen Federal Building in Chicago was locked down after reports of a knife-wielding person inside. FBI is investigating ...

The FBI and other law enforcement personnel responded to a man in the Dirksen lobby who walked into the courthouse armed with ...

Following a nine-hour standoff at the Dirksen Federal Building, a knife-wielding man — who prompted a lockdown and evacuation ...

The man held up a sign that read "call lawyer" during the lengthy standoff, which led to a mandatory evacuation. There were no reports of injuries, and there was no danger to the public, authorities ...

At 7:19 a.m., the thieves jumped the security gate at CPD headquarters, stole the Jeep, and smashed through the gate to ...

Following a nearly nine-hour lockdown for a man armed with a knife at one of the most secure federal facilities in Chicago, the ABC7 I-Team spoke with federal law enforcement experts about the process ...