Crucial DNA evidence allegedly linking Amanda Knox to the killing of British student Meredith Kercher will not be shown in Italian court Friday after a judge agreed to a defense request to delay hearing DNA evidence so they can review a newly revealed video of investigators searching the murder scene.

The court will now hear testimony on how the police searched the murder scene and whether they wore protective gear. Part of what is at issue is a piece of bra strap found weeks after the initial search that prosecutors say has the defendant's DNA.

American Knox, 21, and her former boyfriend Raffaele Sollecito, 25, deny murdering and sexual assaulting the victim.

Kercher, from Coulsdon, Surrey, was found semi-naked and with her throat cut in a rented house in Perugia, Italy.

The 21-year-old Leeds University student was on an exchange program and had only been in Perugia for two months before she was killed.

Jurors in the town have already heard prosecution claims that she was killed after refusing to take part in a drug-fuelled sex game.

Forensic scientists, including the chief of the Italian Scientific Police Unit in Rome, Patrizia Stefanoni, were supposed to give testimony on a foot-long kitchen knife found in Sollecito's apartment after the murder in November 2007.

Click here for photos.

Forensic experts say DNA from Meredith was discovered on the blade.

They claim Knox's DNA was found on the handle of the knife, which they say is compatible with the murder weapon that has never been found.

The experts were also going to detail how DNA from Sollecitowas found on a piece of bloodied bra.

The material is believed to have been ripped from Meredith's body.

The forensics specialists include chief of the Italian Scientific Police Unit in Rome, Patrizia Stefanoni.

Last October, Stefanoni gave evidence in the trial of Ivory Coast drifter Rudy Guede, 22.

He was sentenced to 30 years after being found guilty of murdering and sexually assaulting Kercher.

Besides the knife, the prosecution also claims Knox's DNA was found mixed in blood spots from Meredith found at the scene in the shower and sink.

Click here to read more on this story from Sky News.