Martin Hawkins was a serial killer who raped and murdered several women, mutilating their faces and sexual organs on the belief that the Virgin Mary had told him it was the only way to "stop the sluts from spreading their disease". Upon conviction, he was committed to the State Psychiatric Hospital in Metropolis, where he was examined by a young resident named Amadeus Arkham. Hawkins tells Arkham the story of how he was physically and sexually abused by his father, and the experience inspires Arkham to convert his family home in Gotham to a facility for the treatment of the mentally ill - the Elizabeth Arkham Asylum for the Criminally Insane.
Some time later, Hawkins escapes the facility in Metropolis, and Arkham returns home one day in the spring of 1921 to find that his wife Constance and young daughter Harriet have been raped, murdered and dismembered, with the words "MAD DOG" carved on their chests with a blade. Hawkins is arrested for these crimes and becomes the first patient committed to Arkham Asylum upon its opening.
Amadeus examines Hawkins, who gleefully taunts him with the details of the deaths of his wife and daughter, claiming that they begged him to abuse them, and insulting Harriet by calling her a whore. Amadeus maintains his calm and composure, and his colleagues admire his courage in the face of unimaginable tragedy. But on April 1st, 1922, exactly a year to the day of the murders, Amadeus straps Hawkins onto the electroshock therapy table and electrocutes him with a massive dose of current, condemning him as a "filthy bastard". This incident is later ruled an accident.
In the Batman: Arkham Asylum video game, extracts from Amadeus Arkham's journal narrate Hawkins' murders of Constance and Harriet Arkham, and his subsequent death by electrocution at Amadeus's hands. Later in the game, Batman finds a memorial to Constance Arkham in the asylum; the memorial's plaque has been vandalized, with the words "MAD DOG" scrawled over it.