CHICAGO -- Two CTA passengers were arrested Tuesday night after getting into a fight on a bus in the 6900 block of South Halsted Street. The fight started after one rider laughed at a man who accidentally put a $100 bill instead of a $1 bill in the fare box.

The man who thought he was placing a $1 bill into the fare box was scratched in the scuffle, police said. The other man and others on the bus laughed at him because he became upset when the bus driver told him he could not have his $100 back immediately and would have to follow CTA procedures to get the money back later, police said.

"The other passengers started laughing at him," Wentworth District Captain James Paoletti said.

Paoletti said the passenger who laughed felt threatened by the man with the $100 bill and "in fear of having his clock cleaned," pulled out a small knife or box cutter during the scuffle. "It was nothing extreme," Paoletti said. During the fight, the man who lost his money was slightly scratched, according to Paoletti.

Both men were arrested and taken to the Wentworth District station around 9 p.m. while authorities determined whether charges would be filed. The man who had pulled the knife would likely be charged with misdemeanor battery, Paoletti said. He could not provide ages for either man.