Reports of a man armed with a gun and threatening to kill fellow passengers on a Greyhound bus led to a police chase of the vehicle that started in Wisconsin and ended in northern Illinois.

None of the 40 people aboard the bus bound for Chicago from Milwaukee on Friday night was injured and the suspect was taken into custody after authorities, using spike strips to flatten the tires of the bus, forced the vehicle to stop on Interstate 94 near the Illinois community of Wadsworth. Authorities said they began chasing the bus after getting a call from someone who was on board.

Racine County (Wis.) Sheriff Christopher Schmaling identified the suspect at a Saturday afternoon news conference. Schmaling said Margarito Vargas-Rosas, 33, of Chicago was charged with making terroristic threats and disorderly conduct. Vargas-Rosas is being held at the Lake County (Ill.) jail.

The suspect also made threats of violence against the arresting officers as well as the investigators at the police station, Schmaling said.

One passenger, Patrick Dodd, told the Chicago Tribune that the incident began when the man who said he had a gun started to threaten passengers riding in the back of the bus. Dodd said the man pulled something out of his pants that Dodd believed may have been a weapon.

The sheriff stated Saturday that no gun was found on the suspect, but police plan to search the bus for a weapon.

Dodd and other passengers were left shaken by the ordeal and wondering why it took so long for the bus driver to stop after police began their chase. He said passengers in the back of him were yelling at the driver to pull over.

"He didn't stop after the first spike strip," Dodd said.

Terrance Williams of New Jersey was in the middle of the bus and initially thought police were escorting the bus, not realizing what was happening in the back. But he too was confused about why it took so long for the driver to stop.

"The law is you see emergency lights you pull over," Williams said. "(The police) were in front of us, they were in back of us."

Sheriff Schmaling said the bus driver told authorities that he didn't stop the bus because he thought the squad cars were following another vehicle.