copy of the photograph recovered from Archambaut's apartment and, as Boden resembled the man in the picture, they held him for suspicion in murdering Porteous. Police then turned their attention to the marks on the victim's breasts. Odontological evidence The police contacted Gordon Swann, a local orthodontist, to help prove that the marks on Porteous' breasts and neck were Boden's bite marks, with the intent to verify them as having been left by Boden. As there was nothing in Canadian literature on forensic odontology at the time, Swann wrote to the Federal Bureau of Investigation (FBI) in the United States, hoping for any information on the matter. Swann received a reply from FBI Director J. Edgar Hoover, who directed him to England, where he met a man who had dealt with 20 or 30 cases regarding bite marks. Swann was able to get the information he needed and based on a cast made of Boden's teeth, he managed to demonstrate 29 points of similarity between the bite marks in Porteous' body and Boden's teeth. Conviction The evidence provided by Gordon Swann was sufficient for the jury of Boden's trial to find him guilty for the murder of Elizabeth Porteous and subsequently sentenced to life imprisonment. Boden was the first murderer to be convicted in North America based on odontological evidence. Boden then returned to Montreal to face trial, where he confessed to three murders of Shirley Audette, Marielle Archambault, and Jean Way, and was sentenced to three additional life terms. Boden was sent to the Kingston Penitentiary in Kingston, Ontario, where he began serving his sentence on 16 February 1972. Boden was initially believed to be involved in the death of Norma Vaillancourt, a 21-year-old student killed on 23 July 1968, but denied involvement. In 1994, Raymond Sauve was convicted of Vaillancourt's death and sentenced to ten years in prison. In 1977, Boden was granted a credit card by American Express five years into his life sentence, which he used while out on a day pass from prison in Laval while eating lunch with his social worker in the Kon Tiki restaurant at the Mount Royal Hotel in downtown Montreal. He went to use the washroom and escaped through the bathroom window. He was recaptured several days later at a bar on Mackay Street in downtown Montreal. Three prison guards were disciplined, and American Express conducted an internal investigation to