Two individuals have pleaded guilty to the manslaughter of two men after drugging their victims with a powerful sedative in order to steal from them. Adina Mihai, 31, and Madalin Dumitru, 30, both formerly of Ilford, Essex, entered their pleas at Oxford Crown Court on Wednesday at the start of a trial that had been due to open that day. The pair had originally faced 19 charges, including murder, to which they had previously entered not guilty pleas.
Mihai and Dumitru each admitted two counts of manslaughter – the deaths of Malcolm King, 80, from Bagendon, Gloucestershire, on 20 August 2024, and Gary Mouat, 37, from Banbury, Oxfordshire, on 13 July 2025. They also pleaded guilty to two further counts of unlawfully and maliciously administering poison, involving two other men whose identities are protected by reporting restrictions. Those offences were committed on 13 July and 22 July 2025 respectively. Mrs Justice Brunner KC told the defendants she would pass “substantial sentences of imprisonment” and remanded them in custody. Sentencing is expected at Oxford Crown Court in late July or early August 2026.
How the drugging and thefts were carried out
The court heard that the pair operated a scheme in which they targeted men seeking sexual services. Mihai would pose as a sex worker and arrange to meet the men at their homes, after Dumitru had taken a financial deposit from each victim. Once inside, Mihai would secretly add gamma-butyrolactone (GBL) to the victim’s drink. GBL is a chemical that converts in the body into GHB (gamma-hydroxybutyrate), a potent sedative and sleep-inducing agent. The drug rendered the men unconscious, at which point the defendants stole property from the home. Prosecutor Julian Evans KC told the court the offences were “committed pursuant to an agreement between the defendants to render the individuals unconscious in order to steal property from them”.
The method was directly responsible for the deaths of both Mr King and Mr Mouat. Mr Mouat, who was the managing director of the glass and glazing company CN Glass, died in Banbury on 13 July 2025. Detectives from Thames Valley Police discovered he had been poisoned with GBL and immediately issued a national bulletin to all other police forces, warning them to check for unexplained deaths that might be linked. That bulletin led Gloucestershire Constabulary to re‑examine the death of Mr King, which had initially been deemed non‑suspicious because of a pre‑existing health condition. Forensic links ultimately proved that Mr King had also been poisoned with the same substance.
The two surviving victims, whose names remain protected, were drugged and robbed on separate occasions between 13 and 31 July 2025. No other deaths, poisonings or thefts have been linked to the investigation at this time, but police said they are “keeping an open mind about the possibility of other victims.”
Background of the defendants
During the proceedings it emerged that Dumitru has a background in cybersecurity, having been the founder and chief executive of Cyber Smart Defence and currently chief executive of SCUT – Securitate Cibernetică Unificată. He was also formerly Vice President of the Employers’ Association of Young Entrepreneurs in Romania. The court also heard that Dumitru had been convicted in Romania in April 2021 and sentenced to six years imprisonment for corruption offences, including making false declarations in his wealth statements and continuing to manage companies while in public office. He was found to have failed to declare income from property rentals and the sale of assets, as well as undeclared watches. Mihai’s background was not detailed in court.
The pair were arrested on 31 July 2025 and initially charged on 6 August in relation to Mr Mouat’s death. Further charges in connection with Mr King’s death were brought on 24 April 2026. Prosecutor Julian Evans said the decision to accept the manslaughter pleas followed contact with the families of the deceased men and consultation with the police forces that had investigated the case over many months.
Police statements on the investigation
Thames Valley Police’s senior investigating officer, Detective Inspector Michael Roddy, described the case as an “extremely complex and resource‑intensive investigation”. He added: “Adina Mihai and Madalin Dumitru used drugs to incapacitate men who had been seeking sexual services, before stealing from them. For Gary Mouat, these actions had fatal consequences so I am pleased to have got answers for his family and would like to thank them for their support throughout our investigation.”
Detective Inspector Adam Stacey of Gloucestershire Constabulary, the senior investigating officer for Mr King’s death, said: “Tragically for Mr King, Mihai and Dumitru’s callous and calculated actions had fatal consequences. The tireless work of all those involved in the joint investigation left Mihai and Dumitru with little choice but to plead guilty to manslaughter and administering poison in the face of overwhelming evidence.” The families of both deceased men have requested privacy and have not issued photographs or tributes.
