Dr. John Olsson was an internationally recognized forensic linguist whose work led him to give evidence in court rooms around the world, including in the USA, Australia, Canada and Singapore, in addition to courts in the UK. His main specialty was the authorship of anonymous documents, such as hoax letters, product contamination threats and kidnap and other ransom demands. In addition, he was an expert in linguistic aspects of code-breaking. He worked on every major type of crime from murder to terrorism, assault of all types, fraud and forgery, narcotics distribution, organized crime and kidnap and other forms of extortion.