The decision by the Court of Cassation adds a further twist to a long-running case whose initial handling was sharply criticised by independent forensic experts.
Prosecutors accused Amanda Knox and her ex-boyfriend Raffaele Sollecito of assaulting and killing Kercher in 2007.
They were initially found guilty and sentenced to 26 and 25 years in prison respectively.
In 2011, their convictions were overturned and they were released after serving four years.
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A dry night ahead, with any showers fading away.
Global warming and a strong El Nino weather system has sparked mass coral bleaching, experts warn.
Much of the commentary online focused on Chris Evan's co-host and former Friend's actor Matt LeBlanc.