Between December 2003 and February 2004, at least 17 patients suffered respiratory arrests for then-unknown reasons. While 15 patients recovered soon after, two patients died in January 2004: Anthony Bateman and David Onley. Geen, who was on duty during these incidents, was arrested on February 9, 2004, whereupon a syringe filled with a lethal dose of muscle relaxant was discovered in his pocket.
During his trial, the Oxford Crown Court was told that Geen purposely used potentially lethal doses of drugs to cause patients to stop breathing because he enjoyed the thrill of resuscitating them. He was found guilty in April 2006, and given 17 life sentences. The trial judge recommended that he should spend at least 30 years in prison before being considered for parole. This recommendation is likely to keep him behind bars until at least 2035.
Geen's case was reviewed by lawyers and volunteers from the London Innocence Project. The review found a number of flaws in the original trial, and lawyers came to the conclusion that Geen was "the victim of a major miscarriage of justice."
A leading medical statistician, Prof Jane Hutton, submitted that the Crown's central evidence - that there had been an 'unusual' pattern of illnesses - was of 'no value' because no statistical modelling had been done to show that the pattern was unusual. She found the 'pattern' method to be at grave risk of bias.
Dr Mark Heath, a consultant anaesthesiologist who has testified in US supreme court cases, found the pattern of patient collapses to be totally inconsistent with the drugs Geen was said to have injected in seven cases. Rather than passing out, patients injected with muscle relaxants as the crown stated would be paralysed, unable to breathe but totally conscious and terrified.
Other doctors came forward who decided that the cause of death in Mr Onley, a gravely ill patient who Geen was alleged to have killed, was not a heart attack triggered by respiratory arrest but liver failure.
Mark McDonald, Geen's barrister, has stated that he believes the case against Geen was the product of a "witch-hunt" in a health service terrified of a repeat of the case of Dr Harold Shipman.
A first appeal failed in November 2009. In February 2010, Geen's case was submitted to the Criminal Case Review Commission and a public campaign was launched. Ben Geen is legally represented by the appeals department of GT Stewart Solicitors.