In response to defense motions this week, Monongalia County Prosecuting Attorney Marcia Ashdown says Eddy's rights haven't been violated, and the confession of her alleged co-conspirator should be used as evidence.
The Dominion Post says Ashdown also told the court she doesn't have access to medical or mental health records for Shoaf.
Ashdown did not oppose a request to delay the trial past the week of Oct. 22.
In addition to murder, Eddy is charged with kidnapping and two counts of conspiracy. Shoaf awaits sentencing.
Both are being held in juvenile detention facilities. Their cases are proceeding in adult court.
Benninger also argues that Shoaf's confession should be suppressed because investigators questioned her without her attorney's knowledge or consent.
Prosecutors have said they plan to recommend a 20-year prison sentence for Shoaf and will oppose any move to have her sentenced as a juvenile. She could be sentenced to as many as 40 years in prison.
Shoaf's family issued a public apology but has made no further statements.
Eddy's family has not commented on the case.