Kevar Preston (clockwise from top l.), Mario Elvira, Kevin Ramirez and Jean Salvatierra were arrested Monday in the attack on two brothers in the 4600 block of North Kedzie Avenue. View Full Caption DNAinfo/Josh McGhee; Chicago Police Department (inset)

COOK COUNTY CRIMINAL COURTHOUSE — A 26-year-old Jefferson Park man was attacked by a machete-wielding man while trying to defend his teenage brother on the Brown Line's Kedzie station platform early Monday morning, officials said.

The Jefferson Park man and his brother, 17, were sitting on a bench waiting for the train when a group of four men and three teens walked up and tried to pick a fight, prosecutors said at a court hearing Tuesday.

Erin Meyer details what provoked the alleged attack:

One of them demanded to know what gang the younger brother was a member of, prosecutors said. He denied being in a gang, and another man in the group threw a beer he was drinking to the ground and put a machete up to the teen's neck, officials said.

Mario Elvira, 18, was with a band of six others on the Brown Line platform in Albany Park when he attacked two brothers with a machete, prosecutors said. View Full Caption Chicago Police Department

A third member of the group snatched the teen's hat, and the group surrounded the teen to block his escape, prosecutors said. At that point, the teen's older brother intervened, yelling at the group.

Mario Elvira, 18, who allegedly had the machete, then turned the blade on the brother, prosecutors said. He swung the machete over and over again as the brother tried to protect his head.

The brother was rushed to the hospital with a gaping head wound that required 31 stitches, prosecutors said.

The attack was captured on CTA security video.

Four men were arrested and charged with aggravated battery, robbery and trespassing on CTA property for sneaking past the turn style without paying the fare, according to court records.

In addition to Elvira, those arrested include Kevar Preston, 20; Jean Salvatierra, 23; and Kevin Ramirez, 19. Two 15-year-old boys and a 15-year-old girl were also arrested.

Bail for Elvira and Preston was set at $450,000 each while the judge set bail for Ramirez and Salvatierra at $250,000.

Officials said Elvira resides in the 5300 Block of West Foster Avenue; Salvatierra lives in the 4800 Block of West Belle Plaine Avenue; Ramirez lives in the 1300 Block of West Rosedale Avenue and Preston is from the 3600 block of West Cullom Street.

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