A former South Yorkshire Police constable has been sentenced to three years and four months in prison after an internal investigation exposed her attempt to blackmail a suspect in one of her own cases and subsequently falsify evidence to conceal her actions.
Marie Thompson, 29, who served as a probationary officer in Doncaster, was investigated by the force’s Professional Standards Department (PSD) after suspicions arose over her conduct.
The court heard that in 2023, Thompson used an anonymous email account to contact a suspect she was investigating, demanding £3,500 to keep the allegations against them confidential. The suspect reported the blackmail attempt to police, and the case was — inappropriately — allocated to Thompson due to her prior involvement.
In an effort to conceal her crime, Thompson made a false entry in her pocket notebook, claiming the victim did not wish to pursue the matter. Days later, she sent a second email from the same account, apologising and claiming she had been “desperate” and would cease contact.
An internal PSD investigation was launched after concerns were raised about her conduct. Thompson was arrested in October 2023 and suspended from duty. Investigators later found that the emails were sent from her personal laptop and uncovered evidence of significant gambling-related debts.
Thompson pleaded guilty to blackmail and perverting the course of justice at Leeds Crown Court on 4 September 2025. She was sentenced today (Thursday, 30 October) at the same court.
Following her guilty plea, Chief Constable Lauren Poultney directed that a Regulation 13 notice — used to dismiss probationary officers deemed unfit to serve — be issued. Thompson resigned from the force on 16 October 2025.
Detective Constable Alexandra Furniss, who led the investigation, described Thompson’s actions as “shameful” and damaging to public trust.
“Thompson’s crimes are shameful and cast a shadow over the excellent work being delivered for our communities by policing colleagues driven by fairness, integrity and trust,” DC Furniss said.
“There is no place in our force for officers who fail to live and work by our values and standards. Our work to root out these individuals continues as we strive to maintain the trust and confidence of the public.”
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