Used in many murders but perhaps none more famous than that of Dr Crippen when he murdered his wife Cora. On 17 January 1910, Crippen had ordered five grains of hyoscine, a narcotic poison, from a New Oxford Street chemist. The poison was collected by Crippen on the 19, who signed the register. Shortly after Mrs Crippen disappeared. When her friends asked after her they were told that she had had to return to America because of a relative's illness and that she would have to resign from the Guild.

As time passed, Belle's friends thought it was strange that they failed hear from her. On 20 February, Crippen and Ethel turned up at a dinner and ball that had been organised by the Guild and, on 12 March, Ethel moved into Hilldrop Crescent. Calling themselves Mr and Mrs Crippen, they went to France for five days, leaving on 16 March and staying over Easter. The day they departed, Mrs Martinetti, a music hall friend of Cora's, received a telegram sent from Victoria Station that said 'Belle died yesterday at six o'clock... Shall be away a week. Peter.' Crippen was known to his acquaintances as 'Peter'. Crippen told people that his wife had died in America and had been cremated.

All went well until 28 June when Mr and Mrs Nash, more friends of Belle, questioned Crippen about his wife's death. They had recently returned from a music hall tour of the States and were dissatisfied with Crippen's explanation. Mr Nash got in touch with a friend of his at Scotland Yard. Chief Inspector Walter Dew was asked to investigate.

Dew visited Crippen who told him that he had made up the stories about his wife's demise to cover up the fact that she had left him for another man and he didn't want to face the scandal involved.

Dew left satisfied with the explanation but, after the following weekend, decided to pay Crippen another visit. He was astounded to learn that Crippen had instructed his partner to wind up their business and that he was going to be absent for some time. Dew also learned that Crippen had had the office boy purchase some clothing suitable for a boy.

Dew returned to Hilldrop Crescent and during an exhaustive search of the building discovered some loose bricks in the cellar floor. On prising up the bricks they discovered a heap of human flesh and hair, but no bones. Medical examination of the remains gave the information that the corpse was that of a stout female, who bleached her hair and who had had an abdominal operation. Traces of hyoscine, in sufficient quantities to indicate a lethal dose, were found in various organs.

An arrest warrant was issued for Crippen and le Neve on 16 July. On 20 July the 'SS Montrose' sailed from Antwerp bound for Quebec. The ship's commander, Captain Kendall, noticed two of his passengers, Mr Robinson and his 'son', John, and had his suspicions aroused by their unusually affectionate behaviour. Two days later he radioed to the ship's owners voicing his suspicions. It was the first time that wireless was used in a murder hunt. As the ship steamed into Quebec, a pilot boat came alongside. On board was Dew, dressed as a pilot. He had sailed on board the 'SS Laurentic', a faster ship, and reached Canada before them. Dew arrested them both and they were returned to London. The trial of Dr Crippen opened on Tuesday, 18 October 1910. Crippen's defence was that there was no proof that the remains in the cellar were those of a woman, never mind those of his wife. After a trial lasting four days the jury were out for only 27 minutes before returning with a guilty verdict and he was sentenced to death. The trial of Ethel le Neve began on 25 October and lasted one day. She was acquitted. Crippen was hanged in Pentonville Prison on 23 November 1910 by John Ellis.