to be a form of sexual abuse. When the interest in a particular subject is obsessive, the behaviour may be described as stalking. The United States FBI assert that some individuals who engage in "nuisance" offences (such as voyeurism) may also have a propensity for violence based on behaviours of serious sex offenders. An FBI researcher has suggested that voyeurs are likely to demonstrate some characteristics that are common, but not universal, among serious sexual offenders who invest considerable time and effort in the capturing of a victim (or image of a victim); careful, methodical planning devoted to the selection and preparation of equipment; and often meticulous attention to detail. Little to no research has been done into the demographics of voyeurs. Legal status Voyeurism is not a crime at common law. In common law countries it is only a crime if made so by legislation. In Canada, for example, voyeurism was not a crime when the case Frey v. Fedoruk et al. arose in 1947. In that case, in 1950, the Supreme Court of Canada held that courts could not criminalise voyeurism by classifying it as a breach of the peace and that Parliament would have to specifically outlaw it. On November 1, 2005, this was done when section 162 was added to the Canadian Criminal Code, declaring voyeurism to be a sexual offence when it violates a reasonable expectation of privacy. In the case of R v Jarvis, the Supreme Court of Canada held that for the purposes of that law, the expectation of privacy is not all-or-nothing; rather there are degrees of privacy, and although secondary-school pupils in the school building cannot reasonably expect as much privacy as in the bedroom, nonetheless they can expect enough privacy so that photographing them without their consent for the purpose of sexual gratification is forbidden. In some countries voyeurism is considered to be a sex crime. In the United Kingdom, for example, non-consensual voyeurism became a criminal offence on May 1, 2004. In the English case of R v Turner (2006), the manager of a sports centre filmed four women taking showers. There was no indication that the footage had been shown to anyone else or distributed in any way. The defendant pleaded guilty. The Court of Appeal confirmed a sentence of nine months' imprisonment to reflect the seriousness of the abuse of trust and the traumatic effect on the