Four members of staff have been arrested in connection with allegations of mistreatment and neglect at Blackpool Victoria Hospital.
The four, three woman and one man, are being held on suspicion of administering any poison or noxious thing with the intent to injure and ill treatment or wilful neglect.
The allegations relate to the alleged mistreatment and neglect of patients on the stroke unit in November 2018.
The action today follows the arrest of three individuals, also healthcare professionals at the hospital, in December.
Det Chief Insp Jill Johnston, of Lancashire Police said: “Our investigation into allegations of mistreatment and neglect of patients at Blackpool Victoria Hospital is very much ongoing.
“I understand further arrests could be concerning but I would like to reassure people we have a dedicated team of detectives working on this investigation.
“Our priority and the priority of Blackpool Teaching Hospitals NHS Foundation Trust is to ensure the safety of patients.
“Given the number of arrests and the nature of the allegations, it remains a complex and sensitive inquiry.
“No timescales have been set and I would ask people to remain patient while we continue to conduct our enquiries.
“A number of post-mortem examinations have taken place in connection with our investigation and we are supporting those families who have had loved ones identified as potentially being involved.
"They are being kept fully updated and supported throughout the process by specially trained officers.
“We are working closely with the Trust as well as HM Coroner for Blackpool and Fylde as part of the investigation.”
In January detectives confirmed a murder investigation was ongoing following the death of a woman in her 70s on the stroke unit in November. This is being treated as a separate investigation.
