Michael Anthony Guider was an Australian child sex offender who was widely described in the media as one of New South Wales’ most notorious criminals. In 1996 he was convicted on 60 counts of child sexual abuse involving eleven victims. In 2002 he received an additional sentence after pleading guilty to the manslaughter of nine‑year‑old Samantha Knight, who disappeared from Bondi in 1986 and whose body has never been found.