Charles Edward Weimer is charged with first degree murder-child abuse.
Defense attorneys say Weimer was telling the truth when he told authorities the fatal injuries his fiance's son suffered came from falling down concrete stairs outside their apartment.
But Comanche County prosecutors say the medical examiners report shows the boy was the victim of child abuse.
A doctor who was at the emergency room on the night of the incident was on the stand once again sharing his opinion on the injuries.
He said he is not ruling out abuse.
If convicted, Weimer could face ten years to life in prison.
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