Prosecutor: Knox ex-beau's DNA on victim's bra

It took Italian police investigating the murder of Amanda Knox's roommate three weeks to find a piece of the victim's bra, but when the missing piece was found it was determined to include the DNA of Knox's former boyfriend and co-defendant.

The section of the bra that includes the clasps is the only piece of evidence so far that places Raffaele Sollecito at the scene of the crime.

U.S. murder suspect Amanda Knox is escorted by police officers as she arrives for a hearing in the Meredith Kercher murder trial on Friday.

Knox, 21, of Seattle, Wash., and Sollecito, 25, are on trial for the Nov. 1, 2007, murder of Knox's roommate Meredith Kercher. Both women were studying in Italy and shared a cottage with two Italian women.

A third person, Rudi Guede, 22, has already been convicted of taking part in the murder, which prosecutors claim occurred when Kercher, who was from England, refused to take part in a sex game.

Testimony in court today centered on fingerprints and evidence collection.

Only one fingerprint belonging to Knox was found in the house she had shared with Kercher and two Italian women. Giuseppe Privitera, a police print expert, testified that a print from Knox's right index finger was identified on a glass found in the sink.

A total of 61 prints were taken into evidence at the scene of the crime. Of these, five belonged to Sollecito, said Privitera, two of which were found on the outside of Kercher's bedroom door.

Only one print belonging to Guede was identified, but it was significant. His bloody palm-print was found on a pillow under Kercher's body. The blood was Kercher's blood.

For the second time, the court was shown a video of investigators working at the crime scene. This video was made on Dec. 18, 2007, more than a month after the crime, and shows a very different scenario than what was found right after the murder.

Investigators had returned to the house to collect specific pieces of evidence they had not gathered on the first three days of inspection at the beginning of November. One of the most important things they had come to find was a missing fragment of the victim's bra, the end part with the hooks.

Sollecito's DNA was later found on the hooks of the bra and is the only evidence that puts him on the scene of the crime.

Lawyers for Knox and Sollecito did not challenge the description of the fingerprints. The DNA evidence won't be officially introduced into the trial until next week.

This is a condensed version of a story on the ABC News web site. Read the complete story with photos.