I Believe I can Fly ... I believe I can victimize children....

CHICAGO, Illinois (CNN) -- Chart-topping R&B star R. Kelly was arrested in Florida Wednesday hours after he was indicted by on 21 counts of child pornography, stemming from a videotape that allegedly shows the star having sex with an underage girl, officials said.

A spokeswoman for the Polk County Sheriff's Office said R. Kelly was taken into custody there, but would not elaborate. Allan Mayer, an attorney for the Grammy-winning singer, also confirmed he is in custody.

An Illinois grand jury charged the 35-year-old singer -- whose full name is Robert Kelly -- with 21 counts of child pornography based on the videotape, which police said was recorded sometime between November 1997 and February. Investigators said the girl depicted in the video was born in September 1984, which would make her 17 now.

Chicago Police Superintendent Terry Hillard said FBI evidence technicians have examined the videotape and consider it authentic.

"It's unfortunate to see Mr. Kelly's talents go to waste, but it becomes a tragedy when behavior damages the community," Hillard said.

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-------------------------------------------------------------------------------- State of Illinois v. Robert Kelly (From FindLaw) If convicted, the Grammy-winning singer faces a prison term of up to 15 years and a fine of up to $100,000. His lawyer, Ed Genson, said he would disprove the child pornography charges.

"The charge is that there's a young lady under the age of 18 on that tape and there isn't," Genson told The Associated Press. "That's simply the stance that I'm taking. We're going to court and we'll disprove that she was underage." The girl's family members also have denied that she is featured on the video, Genson said.

Kelly said he would be proven innocent.

"Even though I don't believe any of these charges are warranted, I'm grateful that I will have a chance to establish the truth about me in a court of law. I have complete faith in our system of justice, and I'm confident that when all the facts come out, people will see that I'm no criminal," he said in a statement released through attorney, Edward Genson.

The Chicago Sun-Times received the videotape earlier this year. The newspaper passed the tape along to the sex crimes unit of the Chicago Police Department, which investigated. Illinois law prohibits producing or disseminating child pornography or soliciting a minor to participate in sex acts on tape or film.

Investigators interviewed more than 50 witnesses who went before the grand jury and identified the singer as the person in the video, authorities said. The FBI crime lab in Quantico, Virginia, authenticated the tape, officials said.

"We would not have proceeded if we weren't confident with the identification of the people on the tape," said Cook County State's Attorney Richard Devine.

Devine said the sex acts on the video occurred in Kelly's home in Chicago.

"The indictments hopefully will send a message to sexual predators ... [that] taking advantage of minors will not be tolerated and there are severe penalties," he said.

Bootleg copies of the video are for sale on the street across the country, selling for $10 for VHS and $15 for DVD. Hillard warned that anyone who has bought or is selling copies of the tape is in possession of child pornography.

"It would be my advice to you to dispose of these tapes," he said.

Authorities would not comment on the identity of the girl in the videotape. The Chicago Sun-Times said she was the then-14-year-old daughter of an associate of R. Kelly's, but added that the girl and her parents have denied the allegations.

Kelly is known for inspirational hits such as "I Believe I Can Fly," but also raunchy ones like "Feelin' On Yo Booty." He has also worked as a producer with Celine Dion, Michael and Janet Jackson, and the Isley Brothers.

He has previously settled lawsuits brought by two women who accused him of having sex with them when they were minors. Documents have also shown that Kelly married the late singer Aaliyah, his former protege, when she was just 15. The marriage was later annulled.

A third lawsuit was filed recently by a Chicago woman who accused Kelly of impregnating her when she was a teen-ager and forcing her to have an abortion.

Kelly is married to a former dancer from his touring troupe. The couple have a newborn son and two young daughters.