CHICAGO – A judge on Friday refused to dismiss child pornography charges against Grammy Award-winning vocalist R. Kelly, rejecting arguments that the period in which the offenses were supposed to have occurred was too vague.

Judge Vincent Gaughan of the Cook County Criminal Court said the 14-count indictment against the 36-year-old entertainer would stand and “the evidence is sufficient for Mr. Kelly to prepare a defense.”

Prosecutors have a tape showing Kelly having sex with a girl they claim was underage at the time it was recorded, which they say was sometime between January 1998 and November 1, 2000.

Kelly’s lawyers had sought to have the charges dismissed, saying the length of the period in which the tape was supposed to be recorded made it impossible for him to defend against because he could not provide an alibi for any specific date.

Kelly, whose 1996 single “I Believe I Can Fly” won three Grammies, was originally indicted on 21 counts of child pornography in 2002. Some of the charges were later dismissed.

Prosecutors contend the girl on the tape was 14 years old at the time of the filming. Kelly, who was not in court on Friday, has pleaded not guilty to the charges and his lawyers have said the girl on the tape will not testify against him.