The so-called “Beast of Baltinglass” was reportedly injured during a fight with a group of men in a London bar.
According to sources, Murphy became involved in a pub brawl, not thought to be linked with his dark past.
He was released in August 2010 after serving 10 years out of a 15-year sentence for a savage attack on a 28-year-old woman.
It is believed Murphy has been living in Barcelona, Amsterdam, northern France, and London since he was released from jail.
Though he is currently a free man, Murphy remains a suspect in several unsolved crimes in the Republic.