Due to the circumstances and statements Markov made to doctors expressing the suspicion that he had been poisoned, the Metropolitan Police ordered a thorough autopsy of Markov's body. Dr. Rufus Crompton performed the autopsy, noting a red mark on the back of Markov's leg. He cut a tissue sample from the area, with a matching sample from the other leg. These samples were sent for further analysis at the Porton Down chemical and biological weapons laboratory. There, Dr David Gall, the Research Medical Officer, found a tiny pellet in the tissue sample.