Editor's note: CNN Contributor Bob Greene is a bestselling author whose 25 books include "Late Edition: A Love Story"; "Duty: A Father, His Son, and the Man Who Won the War"; and "Once Upon a Town: The Miracle of the North Platte Canteen.
(CNN) -- So that I could best understand the depth of his revulsion for the crime, the police investigator suggested that I pay a visit to the elevator where it allegedly took place.
The elevator is just a few steps inside the Canal Street entrance to Chicago's Union Station. The train station, in the decades before the jet age, was the indispensable hub for America's interstate travel. It remains, in the Amtrak era, cavernous and rife with echoes. It is as if the structure was designed to make mere mortals feel small.
The vast station, when it is filled with passengers heading to and from Amtrak trains and local commuter lines, can lead a person to half-believe that in the bustle no one notices him.
Unless someone is making it a point to notice.
"He is 27 years old," said Michael MacDonald, an investigator for Amtrak's police department. "He is able to travel by himself. He's a very likeable guy."
The man he was talking about suffers from cerebral palsy. Physically slight, he has only one leg. He has three fingers on each hand. With determination and quiet daily courage, he is able to get around independently by using a motorized chair.
"There are people who hang around the front door and look for victims," MacDonald said. "Prey."
Pickpocketing is usually the crime of choice. Officers inside the train station are on alert for thieves who attempt to relieve travelers of their wallets on escalators or stairways.
MacDonald has worked in law enforcement for 30 years. Some offenses still have the power to infuriate him, because they violate not only the law, but any basic definition of humanity.
As pedestrians stream through that Canal Street door, rushing to make their trains on the lower level, few even glance toward the little elevator landing to the right of the entrance.
On surveillance video recorded in August, MacDonald said, the young man, trying to get to a commuter train, is clearly visible entering the station. Because he is unable to use stairs, he steers his chair to his right, toward the elevator.
Also on the video are two men, MacDonald said, who "follow him right to the elevator. Both get on with him." The elevator is small, relatively cramped, with a low ceiling.
What reportedly happens next is what is so ghastly. The man in the motorized chair has his cash and a cellphone zipped into a satchel strapped to his waist. This is his custom when he leaves the house; he lives with his mother, and the cellphone is his lifeline.
On the surveillance video, the men who have followed him to the elevator -- later identified by police and by the Cook County State's Attorney's office as Demetrius Thomas, 48, and Terrell Jones, 49 -- strike up a conversation with him.
Then, according to investigators, one guards the elevator door to make certain no one else tries to enter, while the other reaches down and takes what he wants from the man in the chair.
They allegedly take his phone and cash. They seem to be in no hurry; because of his missing fingers, he cannot grasp the items as they are taken from him. He does his best to resist, but it is as if the men are casually removing items from a store shelf. Then, leaving him in the elevator, they simply walk away and go back into the city.
The young man, alone in the busy train station, told an Amtrak police officer what had been done to him. ("Nothing like this had ever happened to me before," the young man told me the other afternoon. "I tried to respond to it with as much grace as I could. But after it was over, it just felt like such an indignity.") From the surveillance video, investigators made still photos and showed them around. One officer assigned to Union Station recognized Demetrius Thomas as a man who had been warned to stay out of the terminal. The next time he showed up he was arrested for criminal trespass and, according to MacDonald, said that Terrell Jones had been his accomplice in the elevator robbery.
A Chicago police detective knew where to find Terrell Jones: in Cook County Jail. It seems that, one day after the Union Station robbery, he had been arrested for a crime a few miles away. At the Northwestern Memorial Hospital complex, a 75-year-old woman was visiting her ailing husband. Alone in an elevator, she was easy pickings. Police had apprehended Terrell Jones for allegedly robbing her.
Both men face eight felony counts for what they allegedly did to the young man in Union Station. They have entered not guilty pleas; I asked a representative of the office of the Cook County public defender whether the lawyers assigned to the men would discuss the case or comment on it, and he declined on their behalf. What we refer to as the justice system will now kick in.
Cases such as this one can come and go, news blips competing for the attention of a busy public already barraged by torrents of bad news. Strong-arm crimes against those least able to defend themselves are on occasion described as "petty" when the victim is not seriously injured. Judges sometimes allow offenders to plead to lesser charges, to speed up the process and unclog the overloaded courts system.
The assistant state's attorney prosecuting the case -- Mary Lou Norwell -- specializes in crimes against the elderly and the disabled. It has come to this: The very people whom society as a whole should be most dedicated to helping are instead so often targets of soulless crime that a special subcategory of prosecution has been developed to deal with those who would hurt them.
Once we begin to shrug at the inevitability of such crimes -- once we begin to accept that, in a cold world, this is just the way things are -- we are heading down a dark and sorry path. Because once we stop caring, we, too, have been robbed of something precious.
The young man's cellphone and his money, Investigator MacDonald told me, are long gone; he will never see them. "I count my blessings," the young man told me. "I don't want to be a 'woe-is-me' type. I've never been that kind of person." Out of a sense of duty, he rode a train back into the city so that he could attend a police lineup to identify the alleged offenders.
There will be status hearings and continuances, and eventually, when and if the case goes to trial, the young man will, in his motorized chair, with considerable difficulty make his way to the courthouse to testify. When he entered the train-station elevator that day, the two men who followed him became an unwanted part of his life for years to come. He had no say. The victims never do.
The opinions expressed in this commentary are solely those of Bob Greene.