Beck and Watts were convicted of the torture and murder of 12 year old Noosa schoolgirl Sian Kingi in 1987. Watts confessed to the murder in June 2007.
Watts' confessions emerged during an interview with police re-investigating the evil pair over another murder. They have grilled Watts and Beck independently over the disappearance of Helen Mary Feeney, last seen in October 1987.
Mrs Feeney is classed as a missing person, as her body has never been found.
Watts has denied any involvement with her murder.
Mrs Feeney, a mother of a young boy, disappeared during the couple's eight-week crime spree in 1987.
This is the only unfortunate thing about the death of this woman.