EAGLE, Colo. (AP) – In an often-testy exchange, the judge in the Kobe Bryant sexual assault case questioned Thursday why prosecutors waited until just three days before the start of the trial to ask for a hearing on the reliability of DNA evidence crucial to the defense.

Judge Terry Ruckriegle said he should deny the evidence challenge because it could delay the trial, but he gave prosecutors until Tuesday to more fully explain their objections.

He also held a closed hearing to discuss the roughly 100-item questionnaire prospective jurors were to fill out today as jury selection begins.

In a motion filed Tuesday and made public Wednesday, prosecutor Dana Easter said test results from laboratories hired by the NBA star’s attorneys indicated there was contamination in control samples intended to ensure accurate testing.

No details were included in the filing, but prosecutors said they had concerns about Elizabeth Johnson, a defense expert who testified during a June hearing that the evidence suggests the accuser had sex with another man after her encounter with Bryant and before her hospital examination the following day.

Defense lawyers claim the accuser’s actions were part of a pattern of behavior designed to gain the attention of a former boyfriend.

The prosecution has suggested that semen from another man was transferred to the woman’s body when she put on unwashed underwear before going to the hospital.

Bryant, 26, has pleaded not guilty to felony sexual assault, saying he had consensual sex with the woman at the Vail-area resort where she worked last summer.

If convicted, the Los Angeles Lakers star faces four years to life in prison or 20 years to life on probation, and a fine up to $750,000.