Coulsdon student Meredith Kercher may have been killed by assailants using two knives, according to media reports.
An Italian judge has reportedly instructed three forensic experts to examine the possibility.
A new post mortem investigation is also believed to include the suggestion that Meredith died from suffocation rather than knife wounds.
The 21-year-old, who was studying in the Italian town of Perugia, was found dead in November last year with her throat cut.
American student Amanda Knox, her Italian former boyfriend Raffaele Sollecito and Ivorian Rudy Hermann Guede have been held since November last year on suspicion of sexual assault and murder.
Knox, 20, Sollecito, 24, and Guede, 21, all deny involvement in her death and are yet to be charged with any crime.
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