Maids Moreton murder case gets TV documentary tonight on Channel 4
and live on Freeview channel 276
The film, which is part of the Catching a Killer series, is titled A Diary from the Grave, and details the investigation which resulted in Ben Field, now 29, being sentenced to life imprisonment.
Thames Valley Police will be running a live Twitter Question and Answer session during the documentary on Monday evening.
It will feature the Thames Valley Police Major Crime Unit. The investigation, led by Principal Investigator Mark Glover, pieced together a series of increasingly bizarre clues, which ultimately would lead them to reveal Field's crimes.
On 9 August 2019, following an investigation which began nearly two and a half years previously, Field was eventually convicted of the murder of Peter Farquhar, who died in October 2015 at the age of 69.
He was also convicted of four counts of fraud and two counts of burglary.
The documentary demonstrates the extent of Field's crimes, which involved the 28-year-old pretending to be in a loving relationship with both Peter Farquhar, aged 69, and his neighbour Ann-Moore Martin, aged 83.
Over time, he 'gas-lighted' both of them, poisoning Peter and convincing him that he was losing his mind, and leaving messages from 'God' to Ann on her mirrors in her house, convincing her to change her will in his favour.
When Peter died, he left his house to Ben as well as £20,000, and there was initially no suspicion around this.
It was only when Ann fell ill in February 2017 that her family raised concerns about her relationship with Ben and a police investigation began.
The investigation took place over 26 months and culminated in a 12 week trial between April and July 2019 in which the jury deliberated over 14 days.
The amount of evidence scrutinised by the team was substantial, with 2,671 items recorded, 127 of these being electronic devices to download as well as journals belonging to both Peter and Ben that needed to be carefully read through and transcribed.
On top of that, 1,407 statements were taken and 40 suspect interviews were conducted.
Principal Investigator, DCI Mark Glover said:
"This case is unique in so many ways and is completely unlike any other investigation I have come across in my 31 years of policing.
"Added to that, Ben Field is unlike any other criminal I have ever encountered.
"The documentary shows his deviousness, his arrogance and the true extent of his evil.
"What it also shows is the scale of our investigation, and the sheer amount of work, dedication and expertise from so many people which eventually resulted in Ben being brought to justice.
"I'm really pleased that this has been documented and that people across the country will be able to find out more about this extraordinary case.
"The film should also serve as a warning that people can be vulnerable to criminals in a number of different ways, and the lengths that some offenders will go to in order to exploit them."
Detective Sergeant Natalie Golding and Detective Constable Jenny Chapman of the Major Crime Unit, who worked on the investigation, will be answering questions from members of the public throughout this.
If you would like to ask the officers a question, just tweet using the hashtag #CatchingAKiller