(CBS) — A man trying to help a woman who was being harassed on a city bus ends up in the hospital.

As CBS 2’s Roseanne Tellez reports, Jose Santiago says people were looking out for him, too, and their quick thinking helped lead police to the suspect.

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Santiago says he’d do it again, despite having a lung pierced by the knife wound.

“I was worried for my life. I thought I was going to pass out right there because there so much blood was pouring out,” he says.

The 22-year-old shows the stitches where he was stabbed, he says, trying to do a good deed. He was on the Diversey bus when a fellow passenger took issue with a woman trying to maneuver a baby stroller.

Santiago says he went to the woman’s aid and told her to put her stroller by him and told her, “I’m here for you.”

He thought it ended there, until he got off at Western Avenue and the man followed. The suspect pulled a knife and stabbed Santiago when he fell to the ground.

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One witness chased the man down, and snapped pictures that helped police.

Another witness tended to the wounded Santiago.

“Without him, I could have lost more blood. I could have passed out because I was standing. He’s the one that called 911 for me,” he says.

His sister, who’s angry the bus driver didn’t kick the man off said she thinks her brother did the right thing.

“Always defend someone because not everyone can defend themselves. He’s a hero at the end of the day,” she says.

Santiago’s family says they’re baffled that 23 year old Gildalthi Rodriguez faces only misdemeanor battery charges, instead of more serious charges.

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Chicago Police would say only that there was “insufficient evidence” to support aggravated battery.