In 1969 ex-Inspector Lewis Henry Keaton, gave a tape recorded interview, in which he proposed the theory that the Ripper was a doctor who was collecting specimens of infected wombs for research puposes. Unfortunately, just as he was about to name his suspect as either Dr Cohn or Koch, or someone else whose name he could not recall, who used strychnine on his victims, the interviewer drowned out Keaton's words with interruptions. Keaton did not in fact join the police force until 1891, three years after the cessation of the Ripper murders, so therefore had no first hand knowledge of the Ripper case. Keaton appeared to have confused his Ripper suspect with Dr Thomas Neil Cream, who used strychnine on his victims. Keaton, at the time of his interview, was almost 100 years old.