The pathologist who helped convict killer Ian Stewart for the second time has spoken about how his victim's brain cracked the case.
Evil Ian Stewart, 61, was already serving life for murdering author Helen Bailey, 51, in 2016, when detectives police reopened their investigation into the 2010 death of his first wife, Diane Stewart, 47.
He was found guilty once again last week.
Diane was thought to have died from natural causes after an epileptic fit.
But when Professor Safa Al-Sarraj looked at her brain, which had been donated for medical research, he says it was clear something was not right.
Speaking to The Sunday Times he said: “I think if it had not been kept and had been disposed of, nobody would have been able to find out what happened, but this was the only objective thing in the case where we had a platform to start looking at a different cause of death."
Al-Sarraj, 63, who works on about 100 criminal cases a year with the police, had never worked on anything like it: "This is very unusual. I cannot recall a case similar to this where it was solved after the brain was donated to medical science."
Examining her brain he discovered that the damage was likely to have occurred over a period of 35 minutes to an hour before death, meaning it was not consistent with a fatal epileptic fit, where people die much more suddenly.
He said: "Epilepsy can cause alterations in the heart rhythm so you expect the death to be quick.
“You don't expect the death to be later on. I remember saying to the police I don't think this is straightforward epilepsy.
“Then they told me that she hadn't had epilepsy for 18 years and I said: 'Well, this is now extremely unusual. I don't believe this is right.'"
At Stewart's three-week trial at Huntingdon crown court, the jury was told there were no signs of an epileptic fit, such as tongue biting or injuries from her supposed collapse.
Another expert told the trial that the chances of her suffering a fatal seizure were "one in 100,000".
While handing down a whole life sentence to Stewart after he was found guilty, the judge, Mr Justice Simon Bryan, told him: "It no doubt never crossed your mind that the donation of Diane's brain for teaching and research would lead to your ultimate downfall, as it was to do, and your conviction today for the murder of Diane Stewart."
Detective Superintendent Jerome Kent, of Hertfordshire police, who led the investigation in both cases, encouraged other officers to search for similar evidence.
He said: "I know no other case where police have gone back to recover material that has been left for medical research and subsequently found the evidence.
“I'd certainly be encouraging other police officers to think about samples that might have been taken by the coroner and during those initial pathology examinations and just seeing if they still exist.”
