A man who murdered a teenage babysitter could be offered immunity if he gives up information on the whereabouts of two other women he has long been suspected of killing.
Derek Sam is serving a life sentence for the murder of 16-year-old Queensland girl Jessica Gaudie in 1999.
Police suspect he is also linked to the disappearances of British backpacker Celena Bridge and teacher's aide Sabrina Glassop who vanished decades ago, The Courier Mail reported.
Neither of the victim's bodies have been found - despite repeated searches in the forest surrounding Kenilworth, in the Sunshine Coast, where officers believe their remains are buried.
Derek Sam has been serving time in jail over the 1999 murder of 16-year-old Queensland teenager Jessica Gaudie
None of the victim's bodies have been found - despite repeated searches in the forest surrounding Kenilworth, in the Sunshine Coast, where officers believe the remains are buried (pictured, Jessica Gaudie)
Sam has already served the minimum parole period of his life sentence over the murder of Ms Gaudie.
She had been babysitting his children at their Nambour home, in south-east Queensland, at the time she went missing.
Sam claimed he had picked her up and driven her to a party, though she didn't show up.
Although he has denied the murder, a jury found him guilty and he was jailed for life.
Sam was eligible for parole in 2016, but has been kept behind bars because of a 'no bodies, no parole' law.
Police believe that Sam has refused to give authorities the location of the body of Ms Gaudie as it will lead to the discovery of the other two women.
Detectives are currently building a brief to submit to the Department of Public Prosecutions as they attempt to bring two murder charges against Sam.
Though as they build their case, they are understood to be considering an alternative deal.
In exchange for information on the whereabouts of the
