A widow was on Thursday night beheaded and her body partially burnt in Samogara Village, Kisii County.
The 66-year-old woman, who lived alone in a mud hut, met her death at her doorstep.
Residents said she was killed because she was suspected of practicing witchcraft, although no one wanted to speak on record about the claims.
"We suspect that she was a witch," said a resident, who did not want to be named.
Matongo Location Chief Samuel Ombui could not confirm the allegations, saying they were just village rumours.
Mr Ombui said the killers were unknown, but police officers from the Rioma Police Station had visited the scene of the crime and investigations are under way.
"We are shocked by this bizarre happening. It is the first of its kind here," he said.
The elderly woman's daughter, Alice Nyaboke, said she was at a neighbouring home at the time of the killing.
"We were informed about it by the neighbours at about 3am… we found her lifeless body lying at her doorstep," she said.
She said she did not know why her mother was killed but revealed that attackers had twice before tried to kill the widow.
"About three years ago, unknown people stormed our home and threatened to burn her with petrol. Two weeks ago, her drinking water was poisoned with an unidentified chemical," she said.
The family did not inform the police of the attempts on the woman's life.
Ms Nyaboke rejected claims that her mother was a witch.
The body of the deceased was taken to Christamarianne Mission Hospital mortuary.