Three people were found dead and four others were taken to hospital after a suspected carbon monoxide poisoning at a care home for the elderly in southwest England, police said on Wednesday.
Dorset Police said a 60-year-old local woman was arrested on suspicion of manslaughter on Wednesday evening and remains in police custody.
"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," said Detective Chief Inspector Neil Third, of the major crime investigation team.
Other residents at the Gainsborough Care Home in Swanage were earlier evacuated from the premises to a nearby church hall before being moved to suitable accommodation.
Chief Superintendent Heather Dixey, of Dorset Police, said carbon monoxide poisoning was the investigation's "primary line of inquiry".
A spokesperson for gas network company SGN confirmed that engineers were called to the care home on Wednesday morning, the BBC reported.
The care home has 48 rooms and houses some residents with dementia.
"The families of those who have died have been informed and the coroner has been notified," the force said in a statement.
"At this time there is nothing to indicate any risk to the wider public."
South Western Ambulance Service said separately that it was called to the home at 0420 GMT and sent a hazardous area response team, 10 ambulances each with two crew, and "a significant number of additional resources".
"Two patients were conveyed by ambulance to Poole Hospital," it added.
The care home is run by Agincare, one of the UK's largest independent care providers.
At its last inspection in October 2021 by the Care Quality Commission regulator, the home's standard of care was classed overall as "good".
- AFP