A woman who stabbed a stranger to death outside a nightclub has been found hanging in her prison cell, the Home Office said.
Prison staff tried to resuscitate Louise Giles
Louise Giles attacked 23-year-old Helen Hay with a kitchen knife outside Flares nightclub in Sheffield in July 2004.
The 20-year-old, who was jailed for life in May, was found hanging in her cell at HMP Durham on Friday. She later died on Saturday, the Home Office said.
The Prisons and Probation Ombudsman is investigating Giles' death.
A Home Office spokesman said: "This was a traumatic incident for the staff and other prisoners.
"Our thoughts go out to Louise Giles' family at this difficult time."
During Giles' trial at Sheffield Crown Court, it was revealed she had intervened in an argument between Miss Hay and another women, although it had nothing to do with her.
Giles then took a knife from her handbag and stabbed the woman seven times in the back and chest.
Passing sentence the judge told her she would serve a minimum of 14 years in prison before being considered for release.