A staff nurse has been found guilty of murdering four elderly patients by giving them overdoses of the diabetes drug insulin.Colin Norris, 32, from Egilsay Terrace, Glasgow, who once said he disliked caring for "geriatric patients", killed four women and attempted to murder another while he worked at two Leeds hospitals in 2002.The trial at Newcastle Crown Court, which started in mid-October, heard that suspicions were first raised when Norris predicted the time of death of a patient who slipped into a fatal hypoglycaemic coma later in his shift.Prosecutor Robert Smith QC told the court Norris also said that someone always died on his shifts.But Norris told the court that this was a joke and that as a nurse you "laugh about things you probably shouldn't laugh about".Throughout the case he denied all the charges.Norris was convicted of four charges of murder and one of attempted murder by an 11-1 majority on the fourth day of deliberations.One of his victims, 86-year-old Ethel Hall from Calverley in Leeds, was admitted to the Leeds General Infirmary in November 2002 after she broke her hip in a fall.She had an operation and staff believed she was recovering reasonably well.But a few days later she slipped into a hypoglycaemic coma and suffered irreversible brain damage, while Norris was her nurse.Police were called in to investigate after a blood sample test showed around 12 times the normal level of insulin in Mrs Hall's blood.She died on December 11, 2002, and Norris emerged as a possible suspect.Officers then checked medical records at the LGI and St James's, where he also worked, and discovered that another three elderly women - none of whom were diabetic - had died from insulin overdoses while under Norris's care, between June and October 2002.They were Doris Ludlam, 80, from Pudsey in West Yorkshire, Bridget Bourke, 88, from Holbeck, Leeds, and Irene Crookes, 79, from Leeds.Norris was also convicted of the attempted murder of Vera Wilby, 90, from Rawdon in Leeds, who recovered from an unexpected hypoglycaemic attack in 2002.He will be sentenced on Tuesday.© Independent Television News Limited 2008. All rights reserved.