Evidence tampering in college co-ed murder case?

A man convicted in the brutal killing of an Omaha college student has asked for his conviction to be thrown out, saying a former Douglas County crime scene investigator planted evidence in the case.

In a motion filed in Douglas County District Court, Christopher Edwards' attorney cites David Kofoed's conviction for evidence tampering in a Cass County double-murder case. Kofoed was sentenced in June to 20 months-to-48 months in prison.

The filing says Kofoed collected blood evidence from Edwards' room in the investigation of 19-year-old Jessica O'Grady's disappearance. Her body was never been found. Edwards was convicted in 2007 of second-degree murder and a weapons charge. He was sentenced to 100 years-to-life in prison.