A notorious murderer, who raped and killed a teenager, has been stabbed to death in a maximum-security Jail, prompting a homicide investigation.
Aymen Terkmani, 31, was serving a minimum 33-year sentence in Lithgow Correctional Centre where he suffered a stab wound to the chest on Wednesday.
He was airlifted to hospital but was declared dead by paramedics en route, having also received medical treatment in prison after the attack.
Detectives have started an investigation into the circumstances surrounding the incident but are yet to lay charges, police said in a statement on Thursday.
The prison was locked down and a crime scene was established following the stabbing.
Terkmani was jailed for the 2015 murder and sexual assault of 16-year-old Mahmoud Hrouk.
The teenager's brother spotted his bloodied, half-naked body through the window of an abandoned home in Sydney's Fairfield East the day after Mahmoud told his mother in a cut-off call that he was with his "friend Aymen".
Terkmani's sentencing judge, NSW Supreme Court Justice Lucy McCallum, said the then-21-year-old subjected the youth to "unspeakable violence" before he died.
"The offender subjected the victim to the most brutal and horrific attack, inflicting injuries too numerous to list and too gruesome to describe," Justice McCallum said as she sentenced him to a maximum term of 45 years.
Prosecutors had called for Terkmani, who was 24 years old at the time of sentencing, to be jailed for life.
But Justice McCallum declined to do so due to his young age at the time of the offending.
Terkmani's sentence was backdated to the day the jury delivered a guilty verdict, meaning he would not have been eligible for parole until 2050.
By that time, he would have been 57 years old.
At trial, the court was told Terkmani and his victim had been spending time together at the vacant public housing property on the night of the murder after going to McDonald's for dinner.
No clear provocation was proved for the sustained attack on the teenager, which involved the use of a rolling pin and a toaster as weapons.
