Prosecutors have very little physical evidence to work with in their case against Salvadoran immigrant Ingmar Guandique, who is accused of killing Levy nearly a decade ago.
On Tuesday, jurors heard from an FBI expert who examined hair and fiber evidence. He demonstrated how her tights may have been used to tie her up, NBC Washington's Pat Collins reported. Nothing he found conclusively links Guandique to Levy, the Associated Press reported.
A Smithsonian anthropologist testified that he found evidence of a fracture in the hyoid bone -- a small bone in the neck that can break during strangulation or by accident. A couple of months ago, officials looked for Levy's hyoid bone but couldn't find it, Collins reported.
A "pen pal" of Guandique's also testified Tuesday, saying he mentioned a dead girl in one of his letters, though he didn't write that he'd killed her, but the pen pal asked Guandique to stop writing her, Collins reported.
Levy's disappearance made headlines in 2001 after she was romantically linked with Condit. He was once the main suspect, but police no longer believe he was involved. Condit took the stand Monday and denied involvement with her disappearance.