 Geen was arrested on 9 February 2004, whereupon a syringe containing traces of the muscle relaxant vecuronium bromide was found in his pocket.Geen claimed that he had accidentally taken the syringe home in a pocket of his scrubs after a chaotic day.The Thames Valley Police conducted an investigation involving up to 40 officers, and Geen was formally accused of two murders and of inflicting grievous bodily harm with intent upon 16 patients.