After specialists told an inquest they were certain that Brendan Woolhead died as a result of treatment at the London Welbeck Hospital, Dr Paul Knapman, the Westminster coroner, said: "We are rapidly approaching criminal matters."
Mr Woolhead, a heroin addict, was caught in the IRA bomb at Aldwych, London, in February last year, suffering severe head and pelvic injuries. Eight months later he was admitted to the Welbeck for treatment for his drug addiction.
The hospital used a controversial technique known as "ultra rapid opiate withdrawal" in which the patient is anaesthetised for six hours and given a cocktail of 15 drugs.
Mr Woolhead, 34, suffered convulsions and died 30 hours later. Professor Griffith Edwards of the Maudsley Hospital, an expert in drug addiction, said the Wellbeck Hospital had made "manifestly false" claims about the safety of Mr Woolhead's care. He added: "My view is that this man died as a result of grossly negligent treatment"