A woman has been arrested under suspicion of manslaughter following three deaths at a Dorset care home.

Three residents were found dead at Gainsborough Care Home in Swanage on the morning of Wednesday 23 October. Seven others were taken to hospital, according to Dorset Police.

A 60-year-old local woman was arrested on suspicion of manslaughter on Wednesday evening.

Dorset Police said the deaths were currently being treated as unexplained and possible carbon monoxide poisoning is the primary line of enquiry. Other residents were evacuated to a local church hall as emergency services responded to the incident.

Detective Chief Inspector Neil Third, of the Major Crime Investigation Team, said: “As part of our investigation, we have made one arrest to enable us to establish whether there have been actions or omissions which are grossly negligent and gather as much information as we can about what has happened. It is important to note that the arrest process also provides certain legal protection to individuals and I would ask for the media and public to avoid speculating any further now that legal proceedings are active.”

Gainsborough Care Home is run by Agincare. A spokesperson for Gainsborough Care Home said: “An incident involving the care home took place this morning, and we have been closely working with the lead agencies to manage the welfare of all concerned.

“The wellbeing of residents is always our overriding priority, and part of the local business continuity plan was to transfer residents in a managed way to a local village hall and church, where they remain safe and well.

“We appreciate that this is a stressful and worrying time for those involved, and have allocated extra staffing resources to provide support locally. We are contacting and updating residents’ families.

“We will continue to work with the lead local authority services to return residents into their home at the earliest opportunity, and will provide further updates in due course.”

A spokesperson for Dorset Council said: “We are working with the home’s owners Agincare, emergency services and other partner agencies to support the residents of the care home who have been evacuated.

“Many of the residents are vulnerable people with significant care needs, and so we are working with them to understand how to meet their needs in the short term and identify their next steps.”