A member of staff was among those taken to hospital in a suspected carbon monoxide leak believed to have resulted in the deaths of three people at a Dorset care home. As police and firefighters continued to investigate the tragedy at the Gainsborough care home in Swanage, it also emerged that one of the victims, an 86-year-old woman, had lived at the home with her sister, who survived and was among those evacuated. Two men aged 91 and 74 also died. A 60-year-old woman who was arrested on suspicion of manslaughter over the deaths, which were discovered on Wednesday morning, has been released under investigation. Dorset police said seven people were taken to hospital as a precaution and are not in a serious condition. Police said they were still exploring possible carbon monoxide poisoning as the primary line of inquiry and there was no wider risk to the community. Dozens of residents who were evacuated from the home were looked after in a church hall. One woman, whose 82-year-old mother was among those evacuated, told the Guardian she believed the incident had been a “terrible accident”. The woman said: “My mum has specialist care from ICSD [intensive community support for dementia]. They and my mum’s social worker let me know. I was allowed to see my mum in the church hall. One of the carers who is quite attached to my mum went in on his day off and he was just sat there holding her hand because she knew him. “My mum got moved out last night to another care home. She’s OK but she’s in a very vulnerable position. She couldn’t get to the other home until 10 o’clock last night. She’s got no medication and she’s got no clothes. “I don’t know what happened because it’s such a lovely home. The staff have been fantastic. They had activities. Mum’s room was allowed to be decorated. Their maintenance man was fantastic. I know he put all Mum’s pictures up. I think it sounds like a terrible accident.” The family of the female victim’s sister came down to the church hall, according to a community leader. “[They] were able to see their grandmother and be with her at what was an awful time for them,” they added. “It was heartbreaking.” Police were called at 7.16am on Wednesday after the three people were found dead at the 48-bed care home in Ulwell Road. Charlotte Harris, 34, who used to work in the care home as an activities coordinator, went to help. She said: “Shock is the main thing at the moment. It’s a big tragedy that doesn’t seem real. There’s a lot of sadness.” Police stood guard outside the home, which is close to Swanage seafront, while firefighters continued to carry out checks inside on Thursday. A police crime investigation van was parked outside. Police said the 60-year-old woman was arrested to enable officers to “establish whether there were any actions or omissions that are believed to be grossly negligent, and inquiries will continue into this”. Toni Coombs, the chair of Dorset council’s people and health scrutiny committee, revealed that a member of staff was among those taken to hospital for treatment. Coombs also said many of the residents have significant care needs and they were working with partners to identify the next steps and ensure they are being supported. The home is run by Agincare, a family-owned business founded in 1986 in Weymouth, Dorset, and now employing 4,000 people at more than 90 locations across England. In a 2021 report, the Care Quality Commission rated the home as “good” and said “risks within the home environment were robustly managed”. It quoted a relative as saying: “We don’t see anything unsafe. My [family member] was a fireman and we were brought up with health and safety in mind, and we don’t spot anything unsafe.” Another said: “They are very safety-conscious.”