The remains of Rina Yasutake were found at a house in Helmsley in September 2018. North Yorkshire Police has not disclosed details of how she died.
Her sister Yoshika Yasutake, 54, brother Takahiro Yasutake, 49, and mother Michiko Yasutake, 78, all of Helmsley, were charged with preventing her lawful burial and pleaded not guilty at York Crown Court in October last year.
At a hearing today, the court heard mother Michiko Yasutake has since been declared unfit to stand trial.
Adjourning the case, Recorder of York His Honour Judge Sean Morris said: "I'm renewing bail as before. You must come back to court when your solicitor tells you."
The case was adjourned for a mention on June 25.
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