A convicted killer jailed for drugging and suffocating to death his author fiancée has gone on trial accused of murdering his wife six years earlier after she donated her brain to science, a court heard today.
Prosecutors claim Ian Stewart, 61, is in the dock at Huntingdon Crown Court today 'by a stroke of fortune' because Diane Stewart, 47, chose not to cremate her entire body.
Her brain was reexamined after he murdered his partner Helen Bailey at their Hertfordshire home in 2016. Ms Bailey, 51, who wrote the Electra Brown books, was discovered under the home the couple shared in Royston.
It was initially thought she had died after suffering an epileptic fit but after Stewart was convicted of murdering Ms Bailey, detectives opened an investigation into his wife's tragic death.
Stuart Trimmer QC, prosecuting, told the jury that the case had been made possible as Ms Stewart 'by a stroke of fortune' donated her brain for medical research.
And it the findings from her brain tissues which proved she oxygen to her brain had been 'substantially reduced' in the hour before her death.
Ian Stewart, 61, was convicted of murdering Helen Bailey, 51, pictured together, in 2016, and is now accused of murdering his wife six years before
Stewart was charged with murdering his first wife, Diane Stewart, in Cambridgeshire in 2010
Stewart, who is serving life in jail, is now on trial for murdering Mrs Stewart, 47, the mother of his children. Ms Stewart died at the couple's family home in Bassingbourn, Cambridgeshire, on June 25, 2010.
Mr Trimmer said: 'The Crown say that this defendant intended to kill Dianne Stewart and the only serious issue you have to determine is whether Ian Stewart was responsible for the killing or whether it was a medical accident.
'This defendant murdered his own wife at the home they shared.
'Initially he was able to fool the medical professionals by suggested she had died in the course of an epileptic fit.
'The Crown say that was not the case. Re-examination of this case showed the Crown say that was not true and his explanation for the circumstances of her death can be disproved by the medical evidence.
'In short the Crown say, he killed her.'
The jury was told that the guilty verdict at St Albans Crown Court in January 2017 for the killing of Ms Bailey led to more focus on the death of Stewart's deceased wife, Diane.
Mr Trimmer told the court: 'Dianne Stewart died on June 25, 2010.
'Ian Stewart was at home, alone, with her. At 11.24am he called an ambulance claiming he had found his wife unresponsive, not breathing.'
Helen Bailey was dragged into a cesspit below the garage of the couple's luxury home. Her dog was found with her
Paramedics were called but 'tried in vain' to save her and she was declared dead.
Her original cause of death was given as 'sudden unexplained death through epilepsy'.
Although most of her remains were cremated the jury was told Ms Stewart had donated her brain to medical research which meant that brain tissues was kept.
After the guilty verdict scientists and pathologists re-examined her death and found it was only a one in 100,000 chance that the mum-of-two would have died from epilepsy.
The court heard how it had been 18 years since she had last had a seizure of note and it was 'an extremely low' chance that epilepsy has caused her death.
Instead it emerged there had been a 'substantial reduction of oxygen' to her brain in the hour before her death - which was proven by 'well developed ischemia - a change to the make up of the tissue which could be seen with the naked eye.
'The cause of death was most likely caused by a prolonged restricted of her breathing from an outside source and the account given by Mr Stewart, the only other person on the premises, was
