A woman was set on fire during an argument with a man on a Chicago train Monday night, police said. 

The 26-year-old victim was riding a Chicago Transit Authority train when she got into an argument with a man, 45, around 9:25 p.m., the Chicago Police Department said. 

“That altercation became physical when the offender poured a liquid onto the victim and ignited it, causing the victim to start on fire,” a police statement said.

The suspect fled once the train stopped, police said. On Monday afternoon, authorities said a person of interest was taken into custody.

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The woman got off the train and fell to the ground. The fire was extinguished before first responders arrived. 

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The victim sustained severe burns to her body and was taken to a hospital in critical condition. 

“Just seeing her lying on the ground, and she was kind of hyperventilating and in a lot of pain. You could tell she was in really bad shape. All the medics were down there, and there was a big turnout as far as responders and so forth,” one witness told Fox Chicago. 

The incident is still under investigation.