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A Chicago-area prosecutor on Tuesday asked that anyone who is alleging abuse by singer R. Kelly contact her office to investigate their claims, adding that families of two alleged victims have already come forward.

Cook County State's Attorney Kim Foxx made the request at a Tuesday news conference in Chicago on the heels of the airing last week of the Lifetime docuseries, "Surviving R. Kelly," which chronicles decades of the singer's alleged sexual misconduct.

"In order to have an investigation we have to have victims and witnesses who are willing to come forward with information," Foxx said. "Allegations of domestic violence or sexual assault require someone to say what they've seen, heard or experienced."

The six-part documentary that aired from Thursday through Saturday contains more than 50 interviews. It features testimony from women who accuse Kelly of mental, physical and sexual abuse, as well as interviews with associates and relatives of the singer.

Kelly, 52, has repeatedly denied claims against him.

An attorney for Kelly in Chicago, Steven Greenberg, told NBC News in a phone interview on Wednesday, Foxx's call for alleged victims was "irresponsible."

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“I think that when you go and say, ‘Call us if you’re a victim,’ that you’re inviting impostors and frauds," Greenberg said. "I think if anyone was a victim of wrongdoing, they would have reached out to law enforcement.”

Greenberg also said that neither he nor Kelly have watched the docuseries or been contacted by law enforcement since it aired.

"I have not spoken to anyone. He has not spoken to anyone," he said. "No one has asked us anything."

Greenberg said that there is no evidence his client did anything wrong.

"Over a decade ago, he was found innocent of any wrongdoing," Greenberg told NBC News. "For people to now accuse him of things, they’re just haters trying to ruin his career. How would anyone feel if they were being accused of things they didn’t do?"

Representatives for the musician have declined to comment to NBC News about the series.

Foxx, the first African-American woman to lead the Cook County State's Attorney’s Office, said at her news conference Tuesday, “There is nothing that can be done to investigate these allegations without the cooperation of both victims and witnesses. We cannot seek justice without you.”

She said her office has been contacted by two families of two alleged victims. The families are in the Chicago area, she said.

The State Attorney’s Office has not opened a formal investigation into the allegations.

Foxx said she watched "Surviving R. Kelly" and was "sickened" by it.

"I was sickened by the allegations. I was sickened as a survivor. I was sickened as a mother. I was sickened as a prosecutor," Foxx said. "I worked in this office for a number of years, including in 2008, so the allegations were not new to me."

Chicago police have made welfare checks at properties owned by Kelly in Chicago, including a recording studio, Foxx said, adding that the State's Attorney's Office has not been involved in those checks.