The statement came after a sadistic church warden who murdered a university lecturer following a campaign of physical and mental torture was sentenced 36 years in prison on Friday.
Benjamin Field, 28, killed Peter Farquhar, 69, in order to inherit his house and money.
The Diocese of Oxford said in a statement that there are lessons to be learned from the case.
"The sentencing of Ben Field marks the conclusion of a long, complex and disturbing case," it said.
"It's clear that Ben Field manipulated everyone he came into contact with. We're determined to learn what we can from this extraordinary case.
"The church and wider society needs to be ever more vigilant of those who can be made vulnerable by the likes of Ben Field simply because they are elderly or lonely."
Detectives labelled Field a psychopath and said he would have been an "ongoing danger to society" had he not been stopped.
Oxford Crown Court heard Field secretly gave Mr Farquhar drugs and spiked his whisky, hoping that his eventual death at his hands would look like suicide or an accident.
It was only when the Baptist minister's son began targeting Mr Farquhar's neighbour, Ann Moore-Martin, in the village of Maids Moreton, Buckinghamshire, that his scheme began to unravel.
The sexually promiscuous Field also manipulated Miss Moore-Martin, a retired Christian headteacher, by writing messages on her mirrors purporting to be from God.
He admitted fraudulently being in relationships with the pensioners as part of his plan to get them to change their wills.
Field accepted he had "psychologically manipulated" the retired teachers but denied any involvement in their deaths.
Mr Farquhar, who was torn about his sexuality because of his religion, died in October 2015 while Miss Moore-Martin died in May 2017 from natural causes.
He told the jury he had created fake relationships with Mr Farquhar and Ms Moore-Martin in order to benefit financially from their deaths but had not wished them dead.
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