Four days after Richard Kelvin's body was discovered, von Einem was questioned by the police about the murder. He initially claimed that he had not seen Kelvin and had no knowledge of his whereabouts and stated that on the night of abduction he had been in bed with the flu and was off work for the next week. Police also searched his home in the northern Adelaide suburb of Paradise, and seized a bottle of Mandrax. Von Einem admitted that the drugs were his and said that he used them to help him sleep. He denied having any other drugs in his possession, but police also seized a bottle of Noctec, concealed on a ledge behind his wardrobe. von Einem also allowed police to take hair and blood samples, as well as carpets and other materials for testing.
