A 60-year-old man was arrested Wednesday on suspicion of strangling his 82-year-old mother at their house in Ageo, Saitama Prefecture, sometime around April, police said.
Police said Minoru Hayashi has confessed to strangling his mother, Chiyo Narita, after she told him: "Work. You are only spending money."
The man's 30-year-old son visited the house Tuesday, became suspicious about his father's behavior and later returned with police. They found the the woman's body, clad in pajamas, on a futon.
Hayashi has told investigators that he killed his mother in mid-April.
The investigators quoted Hayashi as saying, "More than two months passed while every day I thought about turning myself in to police."
He told investigators that he burned incense sticks to hide the smell of the decomposing body, police said.