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CHICAGO ( WBBM ) -- An arson investigation is underway after a woman was set on fire while riding a CTA Blue Line in Chicago's Loop on Monday night.

According to Chicago police, a 26-year-old woman got into an argument with a 45-year-old man while on a train at Clark and Lake streets around 9:25 p.m. Police said the fight escalated when the man poured a liquid on the woman and set her on fire.

Police said the woman got off the train and collapsed on the platform. A witness told CBS Chicago they saw the victim jump off the train and bystanders come to her aid.

She sustained severe burns and was taken to Stroger Hospital in critical condition.

CBS Chicago has obtained video of the aftermath, which shows a woman with significant burns on her head.

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