A man who has spent 27 years in jail after being convicted of poisoning his wife, mistress and three others in Mie Prefecture had his fifth appeal for a retrial rejected by the Supreme Court on Jan. 29.The court rejected the special appeal filed by Masaru Okunishi, 71, ruling that the defense had not unearthed new evidence that would be sufficient to overturn the earlier rejection of the appeal by the Nagoya High Court. Okunishi was convicted of poisoning wine served at a local public hall meeting in Nabari, Mie Prefecture, on March 28, 1961, causing five people to die -- including his 34-year-old wife and 36-year-old mistress -- and injuring 12 others.In 1964, the Tsu District Court exonerated him of murder on the grounds of insufficient evidence, but the Nagoya High Court in 1969 reversed the district court's ruling and found him guilty of the murders. In 1972, Okunishi appealed to the nation's top court but his appeal was rejected. In 1977, Okunishi's filed his fifth appeal for a retrial with the Nagoya High Court. After the court ordered an on-site investigation and interrogation of the defendant, it ruled that there was no room to have reasonable doubt about his guilt.The Supreme Court has now sided with the high court in rejecting Okunishi's request. His conviction was based chiefly on the strength of expert testimony claiming the teeth marks left on the wine bottle cap matched those of Okunishi's.In the latest appeal, Okunishi's attorneys presented evidence and experts' opinions that contradicted earlier testimony. Judge Masao Ono ruled that Okunishi's conviction is backed by circumstantial evidence and that his confession while under interrogation is credible.