The brother, sister and mother of a woman whose mummified remains were found on a mattress will not face trial, a judge has ruled. Sean Morris, the recorder of York, decided on Tuesday that the charges – preventing the lawful and decent burial of a dead body without lawful excuse – should remain on file. “These three defendants suffer from an extremely rare mental affliction which has created a unique situation for the criminal courts,” he said. Rina Yasutake, 49, a talented artist who was thought to have attended Cambridge University, was found dead on a mattress in September 2018. Her body had lain there for about six weeks. The Japanese artist, described by locals in the North Yorkshire market town of Helmsley as “reclusive”, was discovered after a pharmacist became suspicious that her siblings were buying litres of surgical spirit and “smelled of dead bodies”. Her sister Yoshika Yasutake, 55, brother Takahiro Yasutake, 49, and mother Michiko Yasutake, 78, pleaded not guilty to preventing her lawful burial in October last year. North Yorkshire police has not disclosed details of how she died. The Crown Prosecution Service (CPS) offered no evidence at York crown court on Tuesday and Jonathan Sandiford QC said it was not in the public interest to pursue the matter to trial. The facts of the case were outlined at a previous hearing before Scarborough magistrates court in 2019, when the prosecution said police had been notified by a member of pharmacy staff that she had grave concerns about excessive quantities of surgical spirit a Japanese couple had been buying. Prosecutor Sarah Tyrer told the court that “reference had been made that they were using it for cleansing an individual called Rina Yasutake”. “The pharmacist noticed – and I quote – that they ‘smelled of dead bodies’,” the prosecutor added. Later that day the police discovered Rina’s body – lying on a mattress in one of the bedrooms “in an advanced state of decomposition to the point of apparent mummification”. Tyrer said it was believed she had been dead for approximately six weeks. On Tuesday, Sandiford said any sentence following a trial would have been limited to a supervision order or an absolute discharge. The matter would be left on file, with the understanding that the three defendants would accept any welfare checks or visits by social services or the police in Helmsley. The judge added that a trial would put the criminal courts “to vast expense and time in these troubled times when really it would be to no end”. Morris described the “highly unusual circumstances” that led to him being asked to allow the case to lie on file. “But unique cases and unique circumstances require unique disposal,” he said. After the discovery of Yasutake’s body three years ago, her former classmate Sarah Matthews said she had been “a very hard-working teenager with a bright academic future”. The pair shared a dormitory at Queen Mary’s boarding school for girls in the late 1980s, and Matthews thought she had gone on to study at Cambridge University. A joint statement from North Yorkshire police and the CPS described the matter as a “very complex, sensitive and sad case”. It said the decision not to proceed had been considered at the highest level within CPS Yorkshire and Humberside, and in discussion with the police. “It was agreed that it was not in the public interest to prosecute, and that the case should be left to lie on file,” it said.