Murder squad detectives have arrested a nurse in connection with the death of a pensioner and are investigating the cases of other patients who were treated on the same cancer ward.
The 25-year-old was arrested on suspicion of administering a noxious substance at Hull Royal Infirmary. The police were brought in to investigate the case after hospital officials became concerned about the death of patient Kenneth Heaton, 79, who died at the hospital in August last year.
Humberside Police are to examine the records of other patients who died on Ward One, where Mr Heaton was a patient.
The detectives are to investigate an estimated 30 deaths that occurred from July 2001 to January this year, which is thought to be the period the nurse was working on the ward.
Ward One employs about 30 people and care for people with blood disorders, such as leukaemia and cancers.
Hull and East Yorkshire Hospitals Trust alerted the police who said yesterday there were no suspicions concerning other members of staff. The nurse has been questioned and released on bail.
Mr Heaton, who was suffering from leukaemia, had a fear of hospitals and had been cared for by his daughter, Margaret Metcalfe, at home in Hull, after undergoing an intensive course of chemotherapy.
Whilst at his daughter's, he developed an infection and went back into hospital in August 2003. Doctors confirmed he had developed pneumonia and began a course of antibiotics.
Mr Heaton began to show improvement and doctors told his family he was beginning to respond to treatment.
But, three days later, his family were informed that he died from the disease.
The death was not considered suspicious at the time so authorities did not hold a post mortem or inquest. Mr Heaton was cremated on 5 September last year.
The police, however, were contacted by the hospital trust on 5 January with their concerns over the death following an internal investigation.