Chad E. Williams is in the Aiken County Detention Center on charges of armed robbery and murder in the death Tuesday of Hubert Ellis.
Lt. Michael Frank, the sheriff's office's spokesman, said it was unclear whether the two men knew each other, although Mr. Williams' home is about 100 yards from Mr. Ellis' mobile home on Duck Wood Lane, where his body was found Wednesday morning.
"You can see the subject's home from the victim's home," Lt. Frank said.
Investigators arrested Mr. Williams Thursday afternoon after an interview at the sheriff's office.
"Our investigation now clearly shows robbery was the motive in this case," Sheriff Michael Hunt said.
Mr. Ellis' son-in-law discovered the elderly man about 9 a.m. Wednesday. He was lying face down in the bathroom doorway of his home.
Aiken County Coroner Tim Carlton said preliminary autopsy results show that Mr. Ellis died of bleeding in the brain, the result of multiple head injuries.
Lt. Frank said that investigators are still trying to determine what the murder weapon was.
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