Forensic tests are being carried out on a knife found in bushes close to the home where a British student was murdered.
The small kitchen knife was found in undergrowth close to Meredith Kercher's student apartment during a fresh search of the scene.
Police sources said that on initial examination the bloodstained knife was "not compatible as the murder weapon, but was being examined all the same."
Several bloodstained tissues were also recovered and have been taken with the knife to a laboratory in Rome.
The discovery comes a month after police revealed an eight-inch kitchen knife had been found with Kercher's DNA on the tip.
On the handle were traces left by American suspect Amanda Knox, 20, - and the weapon was discovered in the kitchen of her boyfriend Raffaele Sollecito's flat.
Both Knox and Sollecito are being held in custody on suspicion of murder along with another suspect, Rudy Hermann Guede, 20.
Kercher was found semi-naked and with her throat cut in the bedroom of the flat she shared with Knox in the Italian city of Perugia six weeks ago.
The discovery of the second knife came just days after Sollecito's lawyer, Marco Brusco, had called for a more detailed search of the scene.
Perugia prosecutor Giuliano Mignini was called in, as well as flying squad chief Giacinto Profazio, who was accompanied by the head of the murder unit, Monica Napoleone.
Besides the knife, the forensic team checked for more fingerprints and took new photographs.
Profazio said: "The knife is being examined, but at this stage we don't think it is connected."
The discovery came just 24 hours after Knox broke down in tears in court and insisted she was innocent of murdering 20-year-old Kercher..