Authorities are saying that a verbal altercation between passengers turned into threats on a Greyhound bus Friday night.
Authorities have identified the man who allegedly made those threats as 33 year old Margarito Vargas Rosas, a Milwaukee restaurant worker who lives in Chicago and had previously been deported.
"(He) has been in our country illegally and has been deported some time ago back to Mexico and by virtue of his actions last night, he's back and threatening to kill Americans," Racine County sheriff Christopher Schmaling said.
Passengers on the bus say that Vargas-Rosas was irate and could not be reasoned with.
"(He was) just saying that he was going to kill us, that he was going to put a bullet in our head," passenger Patrick Dodd said.
Passengers called 911 while the altercation was taking place, but the bus driver didn't stop, unaware of the commotion on board and thinking that police were trying to stop someone else.
"The bus driver had no idea what was aeppening. He thought it was a training exercise," Schmaling said.
A spike strip finally disabled a wheel on the bus and the vehicle came to a stop. With guns drawn, police took the suspect into custody.
No weapon was found, but investigators are still trying to complete a thorough search of the bus.
Vargas-Rosas is being held at the Lake County Jail in Waukegan. Authorities are looking to extradite him back to Wisconsin, where he is facing charges of making terroristic threats.