A man has been arrested at Sydney Airport over the fatal stabbing of a mother of two in Sydney 24 years ago.
The 42-year-old Australian citizen, who lives in Thailand, was detained by the Unsolved Homicide Team after arriving on flight from Kuala Lumpur at 6am.
He was taken to Sydney Police Centre in Surry Hills where police expect to charge him with solicit to murder, accessory before the fact to murder and accessory after the fact to murder.
Rita Caleo was stabbed to death in her Double Bay home, in Sydney's eastern suburbs, in the early hours of August 1990.
Her alleged murder followed the shooting of her brother Dr Michael Chye on October 16, 1989.
Mr Chye was killed while sitting in his car parked outside his Woollahra home.
Despite extensive investigations in the 1990s, no-one was charged over either incident.
Mrs Caleo and Dr Chye's father, Peter Chye, was a senior-ranking officer in Malaysia and their deaths received publicity in Australia and Malaysia.
Detective Inspector John Lehmann said police believe a number of people were involved in the deaths and investigations into the matters remain ongoing.
"Today's arrest is of immense significance to the investigation into Mrs Caleo's death but it is by no means the end of the road for Strike Force Nichola," he said.
"My advice to anyone who was involved in these incidents, even if only by association, is to contact us before we come to you."
A search warrant in relation to the murders is also being executed at a home in Ramsgate.