Matthew Williams, 34, who was caught in a room with the woman with severe facial injuries by police, died after he was struck by a high voltage taser which was being used to apprehend him, the Telegraph reported.
Security staff of the hotel which was also used as temporary accommodation for homeless people, raised the alarm after they broke the door open and discovered Williams red handed.
He had only been released from a long sentence for violence just two weeks ago. The woman died of her injuries in the room of the Sirhowy Arms Hotel in the village of Argoed, near Blackwood, South Wales. Williams had taken the woman there for a drink.
"We were called at 1.23 Am local time on Thursday after a report that a man was attacking a woman in the Sirhowy Arms Hotel. On arrival both the male and female were still at the location," Gwent Police spokeswoman was quoted as saying by the paper yesterday.
The Independent Police Complaints Commission has been called in to investigate Williams' death because he was in police custody after being tasered. A post mortem and formal identification of the man will take place at a later date.