Poisoner may still be working at hospital

The person responsible for deliberately contaminating medical equipment resulting in the deaths of at least three patients at a hospital could still be working there, police warned yesterday.

The authorities at Stepping Hill Hospital confirmed that they were dealing with a series of "criminal acts" as a fourth patient, a man in his forties, was revealed to be critically ill as a result of the malicious tampering with saline solution.

More than 60 detectives are now working on the increasingly complex investigation in Stockport, Greater Manchester, with officers interviewing staff and visitors to the site which has now become a crime scene. A total of 14 patients are believed to have been affected, although detectives indicated that they could begin to review previous deaths once they had a suspect.

However, police ruled out the likelihood of any quick arrest as inquests were opened and adjourned into suspected victims of the saboteur, Tracey Arden, 44, George Keep, 84, and Arnold Lancaster, 71.

Chris Burke, chief executive of Stockport NHS Foundation Trust, sought to reassure patients entering the hospital. He said measures were now in place with police to prevent a repeat of previous incidences following the discovery of a batch of 36 saline ampoules believed to have been deliberately injected with insulin.

The containers were used in drips on at least two wards with victims experiencing sudden drops in blood sugar levels.

Mr Burke said: "This is a criminal act, perpetrated by someone with malicious intent."