During his two-day trial in June 2004, prosecutor Sue Pullen presented evidence that Xiang felt the killings were his destiny. Evidence showed that Xiang had joined the Sporting Shooters Association of Australia in April 2002, and gained a handgun licence in June 2002. One lecturer, Gael M. Martin, told the court that she had expressed concerns about his mental state a week prior to the shootings. Evidence was offered that he harboured delusional beliefs that William Wu was an agent of evil and would destroy him academically, and that his actions on 21 October 2002 focused on fulfilling a perceived destiny to kill Wu.