CHICAGO (WLS) -- An Amtrak police officer shot a 25-year-old man near Union Station in Chicago's West Loop.Amtrak provided few details Thursday morning. Officials only said one of their officers, who was on duty Wednesday night, was involved in a shooting near the train station and that the Chicago Police Department was leading the investigation.Chicago police said the offender is in custody and charges are pending, and an investigation is ongoing. Amtrak said the person who has been arrested is not the Amtrak officer.Amtrak wouldn't go into detail about what exactly led up to the shooting.Family members told ABC7 Eyewitness News Chad Robertson was listed in critical condition at Stroger Hospital. They said doctors told them he may or may not make it.An Amtrak police car was parked outside Stroger's emergency room all day Thursday.The Amtrak officer shot Robertson in the left shoulder around 8:45 p.m. Wednesday about a block south of Union Station, near West Van Buren and South Canal streets, police said.Officers found cash and drugs on Robertson at the scene, police said, but there are no reports that he had any kind of weapon.There were some reports that the officer was responding to a robbery, but the family disputes that claim. They said the shooting was unjustified and that Robertson was heading out of town on a Megabus.They said Robertson is the father of two young children and works construction in Minnesota. They said he went into Union Station last night because it was cold outside, and he wanted to warm up.The family also said that after he was shot, he was struck by a car in the street.The family said they do want to talk to the media and tell Robertson's side of the story. They said they have accounts from witnesses who were there.