Saturday on 48 Hours, a private investigator says Seattle woman Amanda Knox, one of three people accused of killing British student Meredith Kercher in Perugia, Italy, had nothing to do with the slaying and even called on the U.S. State Department to get involved to try and get Knox out of jail.

EXTENDED INTERVIEW: New Revelations From CBS News

Knox and Kercher were roommates, and according the Italian authorities, Knox and two men killed Kercher in some sort of love triangle gone bad.

The CBS investigation disputes that theory and revealed what could be earth-shattering information in the case against UW student Knox.

Watch Peter Van Sant's entire investigation Saturday on KIRO 7 at 10 pm followed by KIRO 7 Eyewitness News at 11.