Ian Stewart, the fiance of celebrated author Helen Bailey, has been found guilty of her "cold blooded" murder, as police reveal they are "re-examining" the death of his first wife seven years ago.
The 56-year-old was convicted of having plied Bailey with sleeping pills for months before killing her and dumping her body in a cesspit under their Hertfordshire home as part of a plot to get his hands on her £4 million fortune.
St Alban's Crown Court heard how the father of two inveigled his way into the successful writer's affections after meeting her in an online bereavement forum following the death of her husband in 2011.
Stewart's own wife, Diane, had died in mysterious circumstances the year before aged 47, and Hertfordshire Police have confirmed they are now "re-examining" the case amid fears that he may have also killed her.
Stewart was convicted of murder, preventing lawfully burial, perverting the course of justice and also fraud in relation to money he transferred from Bailey's bank account to his own after she went missing.
Diane, who had suffered from epilepsy since childhood, was found dead in the garden of their large country home in Bassingbourn in June 2010.
An inquest held three months later concluded that the school secretary had suffered "sudden unexpected death from epilepsy".
But relatives have expressed "huge concerns" over the circumstances and have backed the fresh police probe.
One family member, who requested anonymity, said: "We were told at the time it was an unexplained death and it has worried me, it has been on my mind that it was unexplained."
"He [Stewart] was the only one there when she died... I know her brother and sister have been very concerned. Her mother has been very concerned too, it has been awful for her."
Following Mrs Stewart's death her husband 'received a number of lump sums' including £28,000 from Cambridge County Council, a £33,000 life insurance policy and £16,000 Legal and General policy.
Detective Chief Inspector Jerome Kent from the Bedfordshire, Cambridgeshire and Hertfordshire major crime unit, said: "Diane Stewart died in 2010. There was a coroner's investigation and a post-mortem done and it was concluded that she had died of natural causes. But you would expect me to have a look back over the case to see what happened."
However, the fact that she was cremated may mean the truth can never be fully established.
Bailey disappeared from the sprawling £1.5 million home in Royston, Hertfordshire that she shared with Stewart, on April 11 last year.
He did not report her missing for five days and then told police she had left a note appealing for some space.
For the next three months he played the part of the concerned partner, while her family were left desperate for any news of her whereabouts.
But all the time her body and that of her beloved pet Dachshund, Boris, lay in a tank of effluent beneath the property.
Stewart was arrested on suspicion of murder three months after Bailey disappeared, but refused to accept his guilt, concocting a ludicrous story that his Fiancee had been kidnapped by two former associates of her late husband.
DCI Kent said: "Ian Stewart is a very plausible and convincing individual. When he reported her missing we had no reason to think he was not telling the truth.
"I cannot say when he started to target Helen but I do wonder if the seeds were being sown in the very early days of their relationship. It seems to have been quite a quick process from meeting to selling her house and them moving in with one another.
"He is a very persuasive person. He charmed her, he wooed her and he wormed his way into her life quite early on."
He added: "What he did with her body shows what he thought of her. You would not put a loved one in a cesspit. I do not believe he ever wanted to go through with that marriage. He never bought the engagement ring even though she had chosen the stone and the setting.
"To hide the body in the well knowing every time you went to the loo, where that was going. He had no love for that woman whatsoever and held her in utter contempt."
Stewart, wearing a light blue top, remained emotionless in the dock as the verdicts were delivered by the jury foreman.
The judge, Andrew Bright QC said: "I am quite satisfied this was a murder for gain." He went on "It's plain to me he thought he was going to be a substantial beneficiary following her death."
He now faces life in prison when he is sentenced on today, meaning his two sons, Jamie and Oliver, who gave evidence for the prosecution, have been deprived of both parents, following the death of their mother in 2010.
Reacting to the news of the guilty verdict, Helen's brother John, acknowledged that when he said: "Our thoughts are very much with Ian's family."
He added: "Although this is a victory for justice there can be no celebration. Our families have been devastated and nothing can ever bring Helen back to us or truly right this wrong.
"A long shadow of loss has been cast over the lives of so many who will always remember Helen with love and affection."