West Australian police are investigating links between unsolved homicides in Australia and New Zealand and the movements of a former Australian Navy sailor who confessed to three murders before his death.
Former HMAS Geelong crew member Richard Edward Dorrough reportedly confessed to murdering three people in a suicide note found after his death in August 2014.
The note was found at his Byford home and did not identify the victims.
Police said the state coroner had directed them not to reveal, or confirm, the contents of the note.
So far they have been unable to link him to any unsolved serious crimes and have launched a nationwide appeal for information.
"We are seeking public assistance regarding Dorrough's movements across Australia and even in New Zealand over the past 20 years," WA Assistant Commissioner Michelle Fyfe said in a statement on Saturday.
Ms Fyfe said the WA special crime squad had contacted police in other jurisdictions where Dorrough lived or visited.
"It may well be that members of the public who associated with Dorrough have the information we seek, and we urge them to come forward now," she said.
Dorrough was a suspect in the 1997 disappearance of 21-year-old Kimberley woman Sara-Lee Davey from Broome.
He was charged with the 1998 murder of 29-year-old prostitute Rachael Campbell in Sydney, but was acquitted at trial.
An inquest into Sara-Lee Davey's death is due to be held in April.
Dorrough was 37 when he took his own life.
- Readers seeking support and information about suicide prevention can contact Lifeline on 13 11 14 or Suicide Call Back Service 1300 659 467