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

Michael Murphy, 66, 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.

A Corrective Services NSW spokeswoman confirmed Murphy 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.

Michael Murphy, convicted of the murder of Anita Cobby in 1987. Photograph: NSW police/AAP

“All deaths in custody are subject to a coronial inquest, including deaths resulting from natural causes.”

Cobby had been walking home from Blacktown train station when five men dragged her into a stolen Holden Kingswood on 2 February 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.

Murphy reportedly had cancer.

Cobby’s widower John hoped Murphy’s death “was painful for him”.

“One down, four to go,” he told the Daily Telegraph.