"Please come forward. There's nothing that can be done to investigate these allegations without cooperation between victims and witnesses. We cannot do this without you," Foxx said during a press conference Tuesday afternoon.
Victims or witnesses in the Chicagoland area can either contact their local police departments or the Cook County Sexual Assault and Domestic Violence Unit directly at 773-674-6492.
WATCH: Full Kim Foxx press conference
Foxx said Kelly has been on her radar and her office has been in contact with relatives who are concerned about their family members' contact with Kelly in the last several years. Foxx said all of those concerned relatives are in Cook County and the Chicago area, and that all the possible victims she's been contacted about are over the age of 18.
The six-part docuseries "Surviving R. Kelly," which aired on Lifetime, chronicled sexual misconduct and abuse allegations, including pedophilia and other predatory behavior, that have followed the singer for more than 20 years. Kelly, his attorney and his record label have all repeatedly denied those allegations.
Foxx said she watched "Surviving R. Kelly."
"I was sickened. I was sickened by the allegations. I was sickened as a survivor. I was sickened as a mother. I was sickened as a prosecutor. I worked in this office for a number of years, including in 2008, so the allegations were not new to me," she said.
Foxx said she has also been in contact with Chicago Police Superintendent Eddie Johnson, who told her Chicago police have made well-being checks at properties owned by Kelly in Chicago. Chicago police said in the wake of the docuseries investigators went to an address on the West Side that was referenced in the program, but it did not turn out to be a home or recording studio. Rather, it was a shuttered warehouse.
Police said they have no current complaints against the singer.
Foxx said she would like to open an investigation into any alleged victim's case, but stressed that victims and witnesses are essential for any investigation to begin.
"In order to have an investigation we have to have victims and witnesses who are willing to come forward with information," she said. "Allegations of domestic violence or sexual assault require someone to say what they've seen, heard or experienced."
In 2008, Kelly was acquitted of child pornography charges in Chicago. He has also settled two lawsuits involving allegations of sex with underage girls.
Kelly is reportedly under investigation in Georgia for allegations made against him in "Surviving R. Kelly." Foxx said she has not talked to the district attorney in Georgia, but said if her office obtains any relevant information it will be shared. She said Kelly has a home in the Atlanta area.