Friends of children's author Helen Bailey have asked why her killer Ian Stewart was able to strike again six years after he murdered his first wife.
Ian Stewart had denied murdering Diane Stewart in 2010, but jurors rejected his account that he found her collapsed having suffered an epileptic fit at their home in Bassingbourn, Cambridgeshire.
Yesterday he was found guilty of murdering Diane in 2010 before he went on to kill Helen in 2016 - dumping her body in the cesspit of their £1.5million home in Royston in Hertfordshire.
Ms Bailey's bereavement councillor and close friend Shelley Whitehead told The Telegraph : "It really raises questions about how someone so very evil could literally get away with murder, and do it again.
"Did they look at this bereaved, vulnerable father, this man whose wife has 'died' from an epileptic fit, the father who now has to raise his boys on his own - is he so convincing that they didn't do the proper checks? Or was something overlooked?"
Prosecutors said it is most likely Diane's death was caused by a prolonged restriction to her breathing from an outside source, such as smothering or a neck hold.
Stewart, serving life for the murder of Ms Bailey, told the court he had found Diane collapsed in the garden of their home when he returned from the supermarket.
But a pathologists found it was only a one in 100,000 chance that the mum-of-two would have died from the disease of the brain.
Six years after murdering Diane, Stewart spent weeks poisoning Helen with prescription sedatives.
As she excitedly planned their wedding with the man she referred to in her writing as "the Gorgeous, Grey-Haired Widower", she is believed to have fallen asleep at her computer, overcome by the power of the pills.
He then smothered her in a “heinous” plot motivated by greed and dumped her body in a cesspit under their £1.5m home.
The body of the writer lay undiscovered for three months, alongside the body of her dog Boris, a brown-coated miniature dachshund.
Footage released shows him in the back of a police car being informed of the crucial development in the investigation into Helen's death.
The clip shows police telling the killer he is under arrest before he told them: "You are digging desperate".
As he is read is rights, he tells cops: "What a load of rubbish. Have you nothing better to do?" Moments before, he described his arrest as "a load of s***."
Judge Andrew Bright handed Stewart a life prison sentence in 2017, with a minimum term of 34 years before he could be considered for parole.
He told him: "I am firmly of the view that you currently pose a real danger to women with whom you form a relationship."
Diane was a student at Salford University when she first met Stewart, more than 28 years before he murdered her.
Asked during his trial how quickly he realised Diane was going to be his "companion", Stewart said: "I think almost immediately."
The pair married in 1986 and went on to have two sons.
Following yesterday's verdict, Detective Superintendent Jerome Kent, who led the investigations into both Helen and Diane’s deaths, said: “My thoughts and those of the investigating team are with Diane’s family at this extremely difficult time.
“Both Helen and Diane were extremely talented women who had their lives taken by a man who skilfully controlled them both in the same way by playing on his own frailties and needs.
"He is a calculated killer who planned his attacks to coincide to times when others were away from the house, and he was alone with his victim.
“He is so much a master manipulator, he had the ability to convince agencies of his innocence and kept the truth of what happened from family and friends, keeping those lies going over months and years as well as through the court process.
“In each case, no reports of domestic abuse or concerns about coercive behaviour were reported to any agency. It is often the case that perpetrators are powerful and subtle in their ability to control.
“There is no typical victim of domestic abuse. The fact is it can happen to anyone. We investigate reports of domestic abuse or homicide equally, regardless of age, sexual orientation, race, ethnicity, class or gender.
"Where cases are identified, those who are suffering domestic violence or coercive control should be reassured we are determined and relentless in our pursuit to bring offenders to justice, even years down the line.”
