The 19-year-old woman accusing Bryant made an unannounced appearance in the courtroom Monday as lawyers argued whether her mental health was relevant in the NBA star's trial.
The woman slipped into the building through a fire exit and spent about two hours in the courtroom. Court spokeswoman Karen Salaz said she was told the woman was there to observe.
Prosecutors told the judge the woman was coming but Bryant's lawyers and court observers were caught off guard, reports CBS News Correspondent Lee Frank.
It was only the second time she had appeared in the same room as Bryant since the case began. The other time was March 24, when she was questioned for more than three hours.
By the end of the day, attorneys had wrapped up arguments on the relevance of her mental health, two purported suicide attempts last spring and any evidence of alcohol or drug use.
"We don't know what effect that observation may have on her ultimate testimony at trial," said CBSNews.com Legal Analyst Andrew Cohen.
Bryant was due back in court Tuesday, when defense lawyers and prosecutors were set to discuss what kinds of questions potential jurors should be asked.
Prosecutors want the woman called the "victim." His attorneys want the woman referred to as the "complaining witness," reports Frank. The two sides will argue the legal basis for their choice of labels Tuesday — one of the remaining points of contention before Bryant enters his not guilty plea.
The arguments in the closed courtroom are significant, says Cohen.
"It's going to be monumentally important to the defense, for example, to know whether the alleged victim's prior sexual history can come in," he said. "It's very important for prosecutors, on the other hand, to find out whether Kobe Bryant's statements can come in. I think how these issues go and how they're resolved is going to dictate what happens at trial."
The entering of a plea is not really significant, says Cohen.
"I think we're making a big deal of it because we know that as soon as he enters the not guilty plea, the clock starts to tick for a trial, and that, theoretically, there will be a trial within the next 6 months," he said.
Both sides have told District Judge Terry Ruckriegle they think a trial would take two to three weeks.
Bryant has said he hopes to play in the Aug. 13-29 Summer Olympics in Athens, but he also has acknowledged the case could make that impossible.
"Convenience to the accused is not going to be the primary factor," said Scott Robinson, a defense attorney who has followed the case.
"But he (Ruckriegle) won't ignore it. If Mr. Bryant is supposed to be in the Olympic Games and there's plenty of time outside that period to try the case, then it's possible."
Bryant, 25, has said he had consensual sex with the woman last summer at the Vail-area resort where she worked. If convicted of felony sexual assault, the Los Angeles Lakers star would face four years to life in prison or 20 years to life on probation.
He was expected to fly back to Los Angeles on Tuesday night for the Lakers' playoff game against the San Antonio Spurs, then return to Eagle for the final day of the hearing.