Police arrested an 84-year-old woman Wednesday on suspicion of murdering her 80-year-old husband at their home in Himeji, Hyogo Prefecture, in July, they said.
Hanako Okamoto said earlier that her husband, Akira, was killed by two intruders in a robbery but admitted Wednesday to having made up the story and having murdered him on the evening of July 11 at their house, according to police.
Police allege that Hanako stabbed and beat Akira with a sharp tool and a hammer, which left more than 10 cuts on his body, they said, adding that they found the tools inside their house.
She has not yet said why she murdered him, according to police.
They also said she claimed earlier the "intruders" stole 4.6 million yen in cash from a chest but now doubt the cash was kept there.
The wife also sustained cuts to her face and other parts of her body, but police have yet to determine how she got the injuries.