CHICAGO (STMW) — Four teens — two of them 17 years old and two who are 13 — were arrested Saturday night shortly after they allegedly disabled a CTA bus and beat someone on board.

The four are alleged to have boarded the bus on the 600 block of East 71st Street about 7 p.m. after having disabled the engine by hitting a switch on the side of the bus, police said.

They then allegedly beat and punched a passenger, a CTA spokesman told CBS 2.

Grand Crossing District tactical unit officers responded immediately to the call and arrested two of the teens at the scene, police spokesman John Mirabelli said. Two others attempted to flee the area but were soon caught by police.

A witness on the bus, along with the victim, were able to identify the four as the offenders, Mirabelli said.

The two 13-year-olds have each been charged with a count of misdemeanor battery.

The other two, Darius Love and Anthony Williams, both 17, were expected to appear at a bond hearing Sunday, Mirabelli said. Love, of the 700 block of East 90th Place, has been charged with a misdemeanor count of battery and a felony count of robbery. Williams, of the 7200 block of South Evans Avenue, has been charged with a misdemeanor count of battery and a felony count of attempted robbery.

Earlier reports said the driver of the bus is the one who was attacked. But the CTA said it was a passenger, not the driver.

(Source: Sun-Times Media Wire © Chicago Sun-Times 2012. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed.)