The man accused of killing 12-year-old Amber Harris of Omaha appears to be in even more trouble.

Douglas County Corrections officials say Roy Ellis is under segregated lockdown -- the highest level of security at the facility.

Officials say Ellis threatened a female guard. Because of that threat, they say, Ellis is now restrained and allowed out of his cell for only one hour a day.

Ellis is awaiting trial on murder charges in the death of Amber, who was last seen November 2005 getting off her school bus. Her remains were found six months later in a city park.

Authorities say DNA evidence links the murder to Ellis, a convicted sex offender.