A convicted murderer kicked and punched a fellow prison inmate, breaking his jaw and four front teeth, in a row over bunk beds, Lewes Crown Court heard.
Gill Montgomery was murdered by Hakan Yagiz in 1995
Paranoid schizophrenic Hakan Yagiz, 34, admitted causing Wayne Kingdom grievous bodily harm when he was on remand in Lewes Prison last October.
Sentencing him to indefinite detention, Judge David Rennie said the public needed to be protected from him.
Yagiz stabbed disabled Gill Montgomery, 53, at her home in Hastings in 1995.
After the killing, committed during a bungled burglary, Yagiz, who has dual nationality, fled to Turkey.
He joined the Turkish Army but was tracked down by British detectives who had raided his home after the killing and found blood-stained clothes and the murder weapon.
Turkish authorities refused to extradite him but tried him using witness statements sworn in front of a British magistrate.
He was found guilty of murder and sentenced to 36 years' hard labour but later freed under a government pardon.
He returned to his family home in Hastings and was on remand accused of common assault and battery on his sister when he attacked Mr Kingdom, the court was told on Thursday.
After sentencing, Mrs Montgomery's sister, Elspeth Pratt said she was relieved the public was safe from Yagiz and that he was receiving treatment for his "obvious" mental illness.