The panties were retrieved in a May 2001 search of Levy's apartment after her disappearance. Her body was found more than a year later in Washington's Rock Creek Park.
The biologist, Alan Giusti, testified that no DNA was recovered from underwear and tights recovered from the crime scene, CNN reported.
Regarding lab tests of the underwear from Levy's home, Giusti said, "The sperm DNA profile was compared to and matched to Gary Condit."
Condit was a Democratic congressman from California at the time. He testified Nov. 1 and refused to say whether he had sex with Levy. He was never a suspect, but was questioned.
Prosecutors say Ingmar Guandique, a reputed member of the Salvadoran Mara Salvatrucha gang, attacked Levy as she was jogging and killed her when she starting screaming.
There is no physical evidence linking him to the assault, and prosecutors Wednesday asked the judge to drop two of the six counts, including first-degree sexual assault. Guandique still faces first-degree murder, kidnapping and robbery charges.