The department, which has been dogged by embarrassing allegations of misconduct in recent years, began investigating the Pittsburgh claims after video of the alleged incident was posted on YouTube.
The video apparently shows about 15 police officers in riot gear posing for a photo with a man they detained kneeling in front of them.
Kyle Kramer, the 21-year-old University of Pittsburgh student forced to pose with police, was returning to campus from a pizza parlor when he was detained by police who were rounding up protesters, his attorney Cristopher Hoel told The Associated Press on Friday.
"He was a college student arrested for walking on campus. That seems to me to make him a victim," Hoel said.
Kramer faced a preliminary hearing Wednesday on misdemeanor charges of failure to disperse and disorderly conduct. Hoel said his client is innocent of both charges.
The department issued a statement saying the officers were working in Pittsburgh on their own time, but that they were still representing the city of Chicago.
"The Chicago Police Department does not tolerate misconduct by any of its members, regardless of where it might occur."
It's possible the officers violated Kramer's constitutional rights, as well as internal departmental rules, said Craig Futterman, a University of Chicago law professor who has studied the department and allegations of police brutality extensively.
If the officers were retaliating against Kramer for something he said that offended them, it is possible they could have violated Kramer's First Amendment right of free speech. The officers also might have violated Kramer's 4th Amendment right against unreasonable search or seizure, Futterman said.
Some fellow police officers declined to comment publicly about the investigation. But they pointed to a popular blog
- Second City Cop - that blasted the officers for heaping more ridicule on a department dogged by several recent embarrassing incidents, including the beating of a female bartender by an off-duty officer.
"How do you even begin to defend something like this?" reads the blog. "You can't it's impossible... You are embarrassments."
Pat Camden, who spent more than 30 years with the department and was its spokesman for several years, harshly criticized the officers for damaging the reputation of a department that has been trying to rehabilitate its image that was hurt by several incidents, including one, captured on film and shown worldwide, of an off-duty officer beating up a female bartender.