Officials chased the bus from Racine County into Lake County, Illinois.
Illinois State Police were notified of a pursuit out of Wisconsin involving the bus, police said. Spike strips were used to stop the bus on southbound I-94 near Rosecrans Road.
Approximately 40 passengers aboard the bus have been safely removed - and there are no injuries reported.
Authorities received a call for a disorderly and possibly armed person on a Greyhound bus on I-94 around 10 p.m., the release said.
A person on the Greyhound bus made threats to harm passengers according to public safety radio transmissions. The suspect is in custody, ISP said.
The pursuit started on Interstate 94 in Racine County, Wisconsin around 10:06 PM on Friday, January 12th and traveled south down the interstate into northern IL.
The Illinois State Police said they are investigating whether the man was carrying a gun.
This is a developing story.