A 27-year-old woman was sentenced to eight years in prison Thursday for her role in the slaying last fall of her mother, whose body was found in an apartment in Kofu, Yamanashi Prefecture, in February.

The Shizuoka District Court's Numazu branch found Emi Takanezawa guilty of murdering her mother, Eiko, 53, on Oct. 28 last year. Prosecutors had demanded a 12-year prison sentence.

The murder took place while the accused and the mother were living a vagrant, communal life with several other people, moving from one place to another.

Presiding Judge Sachiko Takahashi denounced Takanezawa's act as "brutal" -- killing her own mother, who could not put up any resistance after having been subject to violence for an extended period.

"It is impossible to imagine the mother's sadness," the judge said.

At the same time, the judge determined that Takanezawa was in a mentally unstable condition when she committed the crime.

According to the court, Takanezawa conspired with Seikaku Uehara, 36, to kill her mother in a rented cottage in the village of Hakuba, Nagano Prefecture, and then they left her corpse in the Kofu apartment.

Uehara was the leader of the group of vagrants, including Takanezawa and the mother, who led a communal life.

Takanezawa killed her mother because their relationship had become unpleasant, the court said.