See his autobiography (2007); I. O'Connor, Arnie & Jack: Palmer, Nicklaus, and Golf's Greatest Rivalry (2008).
Jack William Avery was a War Reserve Police Officer who was murdered in Hyde Park, London in July 1940. Avery was stabbed to death by Frank Cobbett, after Avery approached him. Cobbett was originally sentenced to death, but eventually served 15 years in prison instead.
In 2007 the Metropolitan Police announced that a memorial to Avery would be unveiled in Hyde Park.