Two ambulance workers have been arrested over the deaths of six adults, police have said.

The investigation was launched in 2023 and last year a man in his 30s, from West Wiltshire, was arrested on suspicion of six counts of gross negligence manslaughter and four counts of ill-treatment or wilful neglect by a care worker.

A 59-year-old woman was also arrested on suspicion of gross negligence manslaughter in March this year. Police have only released details of the investigation and arrests now.

The two South Western Ambulance Service workers have been released on bail, Wiltshire Police said. "We can confirm a major investigation is under way relating to several adult deaths in and around Wiltshire," said Det Ch Insp Phil Walker from the force's major crime team. "Our focus is on supporting the families and loved ones of those who have died," he added.

Det Ch Insp Walker said the investigation has been ongoing since an initial report in 2023. The man in his 30s was arrested in June 2024. "Detailed inquiries have been undertaken since to ascertain the facts," he added.

A spokesperson for the ambulance service said it started an internal investigation as soon as it became aware of concerns and had since been "working closely" with police. The service said the two workers were "immediately relieved of all duties, including the treatment of patients," adding one of the individuals is no longer employed by the trust.

"We would like to reassure people that this is an isolated situation and there is no ongoing risk to patients. Please continue to call 999 in a life-threatening emergency," the spokesperson added.

According to the Crown Prosecution Service, the offence of gross negligence manslaughter requires the breach of an existing duty of care, which gives rise to a serious and obvious risk of death.

South Western Ambulance Service was most recently inspected by health watchdog the Care Quality Commission in 2022 and was rated as "good", having made improvements since previous inspections. The trust was rated as "outstanding" for care and "good" for its response times, effectiveness and leadership. Its emergency and urgent care services was rated as requiring improvement.