(CNN) A 33-year-old man faces felony terror charges after threatening to kill passengers on a Greyhound bus headed to Chicago from Milwaukee, authorities said.

Law officers chased down the bus and arrested the man without incident near the Wisconsin-Illinois border Friday night after a passenger called 911 to report a gunman on board, according to Racine County, Wisconsin, Sheriff Christopher Schmaling.

The man allegedly implied that he had a weapon but none has been found, Schmaling said. The bus was being searched Saturday.

The suspect, identified as Margarito Vargas-Rojas of Chicago, was charged with making terroristic threats, a felony, and disorderly conduct, Schmaling said.

Vargas-Rojas, who works in Milwaukee, allegedly threatened to kill officers transporting him to jail as well as investigators who interviewed him, Schmaling said. The suspect is undocumented and had been previously deported, the sheriff said. Vargas-Rojas' status and whether he has an attorney could not be determined Saturday.

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