CHICAGO (AP) — Prosecutors rested their case in R. Kelly's child pornography trial after a day of sensational testimony about alleged trysts, extortion plots and a duffel bag full of sex tapes.

Star prosecution witness Lisa Van Allen cried on the witness stand, pausing to regain her composure, as she described several alleged three-way sexual encounters with the R&B star and the alleged victim, some of which she claimed Kelly videotaped.

Van Allen, 27, also told jurors in more than three hours of testimony Monday that Kelly offered her $250,000 last year to recover a tape of one of the trysts.

An angry Judge Vincent Gaughan told Chicago Sun-Times attorney is threatening to issue a warrant for the arrest of a Chicago Sun-Times reporter.

Judge Gaughan wants to know how reporter Jim DeRogatis got hold of the sex tape at the heart of the case in 2002. He did not appear for a morning hearing regarding his testimony at Kelly's trial.

Gaughan has rejected arguments that the reporter's actions should be privileged under the First Amendment and that he shouldn't have to appear.

During cross-examination, a defence attorney accused Van Allen of plotting to extort money from the singer, which she denied. Under further questioning, she admitted she once stole Kelly's $20,000 diamond-studded watch from a hotel.

"Van Allen is an admitted thief and liar who wouldn't know the truth if she tripped over it," Kelly's business manager, Derrel McDavid, said in a statement.

Kelly, 41, faces up to 15 years in prison if convicted of child pornography for allegedly videotaping himself having sex with a female prosecutors say was as young as 13. He has pleaded not guilty and both he and the alleged victim, now 23, deny being on the video — which is separate from those Van Allen testified to being on.

The state, which called more than a dozen witnesses over two weeks, rested its case after Van Allen's testimony. Jurors will get Tuesday off before the defence begins its presentation on Wednesday.

Van Allen told jurors Monday she first had sex with Kelly and the alleged victim in 1998. Kelly would have been around 30 years old at the time, Van Allen about 18 and the alleged victim would have been 14, according to prosecutors' estimates.

Van Allen said Kelly told her then that the alleged victim was 16. The age of legal consent in Illinois is 17. The three-way sex took place in the same home on Chicago's North Side where prosecutors say the sex tape at the center of the case was made, Van Allen told jurors.

She said she began crying during a second sexual encounter in 1999 with Kelly and the alleged victim, causing an upset Kelly to pick up the video camera and leave the room. She said that encounter took place at the house's basketball court.

"I started crying ... because I didn't want to do it," Van Allen testified. She said Kelly complained that her crying ruined the footage and that he never kept tapes during which she cried.

A final three-way encounter occurred in a trailer during a video shoot in Chicago in 2000, Van Allen said. When someone came to the trailer door, the alleged victim "had to run into the bathroom naked" because Kelly did not want others to see her there, she told jurors.

Several months pregnant, Van Allen, from Georgia, initially appeared relaxed on the witness stand and smiled frequently. But she wept when she discussed the second alleged encounter. Prosecutors paused for two minutes as she dabbed tears from her face.

Kelly looked on from across the room as Van Allen testified, at least once appearing to shake his head and other times staring at his folded hands.

Van Allen told jurors that Kelly offered her $250,000 last year to recover a tape of one of the encounters with the alleged victim. She said acquaintances of hers took the tape from Kansas City to a Chicago hotel, where it was handed over to a Kelly associate who paid $20,000 in cash.

Van Allen portrayed Kelly as obsessed with videotaping his sexual exploits, testifying that he even carried around a duffel bag with his homemade sex tapes in it.

"He carried it everywhere with him," she said. "Wherever he was at, the bag would follow him."

Van Allen said she first met Kelly at the making of a music video in Georgia about 10 years ago. She later appeared in several Kelly music videos, including one for the song "I Wish," in which she braids the singer's hair. During a 1998 Kelly concert tour, Van Allen said she simulated having sex with the singer in front of the audience.

"You didn't cry then, did you?" asked defence attorney Sam Adam Sr., who repeatedly suggested Van Allen's tears in court were disingenuous.

Before Van Allen took the stand, Judge Vincent Gaughan advised that she had been appointed an attorney, saying some of her testimony might be "self-incriminating." She was granted immunity by prosecutors.

Van Allen said she approached prosecutors about testifying in the case only several months ago — six years after Kelly was charged.

"It's the right thing to do," she told jurors.

But Adam said Van Allen had ulterior motives when she contacted prosecutors in March, including to help get a reduced sentence in a weapons case for a man she lives with.

Adam also noted that Van Allen told prosecutors only Monday that she stole Kelly's watch in 2001.