Martin "Mad Dog" Hawkins is a character in the Batman mythos. He was a mass murderer who targeted women, and was one of the causes for why Amadeus Arkham, the man who set up Arkham Asylum, went mad.
Martin was beaten and sexually abused by his unloving father from an early age, which made Mad Dog go insane. He grew up into a disturbed man who would cut himself in order to feel something. One day as he was driven further into insanity, he claimed to see visions of the Virgin Mary who told him to go out and kill women, destroying their faces and sexual organs in order to "stop the dirty sluts from spreading their disease".
He killed many women before he was finally caught and sentenced to stay in the State Psychiatric Hospital in Metropolis. Once there, he was treated by Amadeus Arkham.
When Amadeus went back to Gotham City and set up Arkham Asylum, he went back home on April 1 to find that Mad Dog had broken into his house, murdered his wife Constance, and had sexually abused his daughter before decapitating her and putting her head in a dollhouse. This was one of the factors which eventually drove Amadeus mad.
Mad Dog was captured again and sentenced to Arkham, where he took great pleasure in taunting Amadeus by calling his daughter a slut and telling him about the murder. Amadeus listened to the taunts and took them in his stride, until the anniversary of the murder where he strapped Mad Dog to a table and electrocuted him to death. Martin Hawkins' death was treated as an accident.