Citing a lack of evidence, Sapporo prosecutors on Wednesday released a 50-year-old woman suspected of murdering a 71-year-old female acquaintance in the Hokkaido town of Shintotsukawa in October.
The Sapporo District Public Prosecutor's Office released the woman as it could not compile enough evidence to indict her within the legal time limit, prosecution sources said.
The woman was a suspect in the Oct. 15 fatal stabbing of Asako Suzuki.
It is rare for prosecutors to release homicide suspects, having failed to bring the case to indictment.
Prosecutors in Sapporo will continue to investigate the murder, the sources said.
The woman was arrested in the early hours of Oct. 17 on suspicion of having stabbed Suzuki with a knife at the victim's home.
Following the woman's arrest, the Hokkaido Prefectural Police announced that she had confessed to the crime. The woman's lawyer said later in the day, however, that she had denied killing Suzuki, claiming she had been coerced by police into a confession.
On Oct. 22, she was moved from a jail at the Takikawa Police Station to a detention center in Iwamizawa, some 40 km to the south, after her lawyer claimed her right to silence was being breached at Takikawa.