Benjamin Field, the son of a Baptist minister, was five days away from possibly being selected for ordination when he was arrested.
The 28 year old was found guilty at Oxford Crown Court of killing Peter Farquhar, a member of St Mary's (Stowe parish church), in order to inherit his house and money.
He also persuaded retired headmistress Ann Moore-Martin, a Catholic, to change her will in his favour and wrote messages on the mirror claiming to be from God.
He was arrested when her niece complained to the police, Miss Moore-Martin died two months later of natural causes and Mr Field was cleared of conspiring to kill her.
The Times revealed that at that point in March 2017 he was just five days away from a Bishops’ Advisory Panel (BAP), a significant part of the process to being approved for ordination training.
He had asked Rev Stephen Bushell, a trained psychotherapist, to be his spiritual director. Mr Bushell contacted the Diocese of Oxford in January 2017 with "serious concerns" about Mr Field and if he had been selected he would have had procedural psychological assessment.
Mr Field grew up in Olney Baptist Church, where his father Rev Ian Field resigned as minister in April this year.
The Scottish Daily Mail wrote in January 2018 that Benjamin Field also preached at Olney Baptist Church in October 2017, two years after Mr Farquhar's death, on the commandment not to kill, saying 'But what about as an end to people's miserable conditions or for the greater good?'
He admitted during the trial that he did not believe in God and was just attending church to find "potential targets".
Benjamin Field was confirmed at Stowe parish church in 2015 and gained positions in the church as deputy church warden and parish council secretary - which he used to alter the meeting's minutes and add comments about Peter Farquhar's supposed declining health.
He was removed from both roles in March 2017 when the church became aware of the police's activity and he was no longer a member of the congregation.
The police now want to ask Mr Field about the deaths of two others on the same street as Mr Farquhar and Miss Moore-Martin.
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