Blake Davis, 3, will not be on the witness stand during the trial of Bobby Cutts Jr., The Plain Dealer of Cleveland reported.
The boy's grandmother, Patti Porter, told police she found Blake alone when she went to check on her daughter, Jessie Davis, at her Lake Township apartment.
"Mommy's in the rug," she said Blake told her.
A police sergeant said Blake told him, "Daddy's mad."
Testimony is scheduled to begin Monday in Cutts' trial for capital murder.
Cutts, a former police officer in Canton, led investigators to Davis' body more than a week after her disappearance.
Stark County Judge Charles Brown denied a motion to move the trial out of northeastern Ohio and ruled that a reporter for the Canton Repository can be called as a witness.