One of NSW’s most notorious killers, convicted of murdering Sydney nurse and beauty queen Anita Cobby, has died in jail.

A Corrective Services NSW spokeswoman confirmed Michael Murphy, 66, died at Long Bay Hospital about 11.55pm on Thursday.

“The Corrective Services Investigation Unit, which is part of the NSW Police Force, is investigating and will prepare a report on the death,” she said on Friday.

Murphy was one of five men – including his brothers Leslie and Gary – found guilty of raping and killing the 26-year-old in a paddock in western Sydney in 1986.

All were sentenced to life in prison, never to be released.

Ms Cobby’s widower John hoped his death “was painful for him”, telling The Daily Telegraph “One down, four to go”.

“One down, four to go.” Anita Cobby killer Michael Murphy dies in jailhttps://t.co/YmvRbTUnLt pic.twitter.com/59uRcyJts5

— The Daily Telegraph (@dailytelegraph) February 21, 2019

Ms Cobby was walking home from Blacktown train station when five men dragged her into a stolen Holden Kingswood on February 2 in 1986.

They drove her to a secluded paddock where she was raped and beaten, then had her throat slit and was left to bleed to death.

The Corrections spokeswoman said all deaths in custody are subject to a coronial inquest “Including deaths resulting from natural causes”.

Murphy spent most of his incarceration inside Long Bay’s maximum security wing.

He was moved into palliative care last year reportedly suffering liver cancer.

-with AAP