Perry Kouroumblis, 65, appeared bleary-eyed as he sat in the dock of the Melbourne Magistrates Court on Wednesday after arriving on Australian soil on Tuesday night.
He was extradited from Italy to face two charges of murder and one count of rape, three months after he was arrested at a Rome airport.
Kouroumblis was interviewed by Victorian detectives for several hours on Wednesday before he was formally charged over the January 1977 killings.
It's alleged he murdered Suzanne Armstrong, 28, and Susan Bartlett, 27, at their Collingwood home in Melbourne's inner north between January 10 and January 13.
He is also accused of raping Ms Armstrong during that time frame.
The two friends were found dead with more than two dozen stab wounds at their Easey Street property, while Ms Bartlett's 16-month-old son Gregory was left unharmed in his cot.
During Wednesday's brief court hearing, Kouroumblis' lawyer Bill Doogue told the magistrate his client had no custody management issues.
Susan Bartlett (left) and Suzanne Armstrong were murdered in 1977. (HANDOUT/VIC POLICE)
Kouroumblis, sporting a long white beard and dishevelled hair, stared straight ahead as the alleged victims' siblings watched on.
He was remanded in custody and will return to court in February for a committal mention hearing.
Outside court, Ms Armstrong's sister Gayle told reporters she was ecstatic Kouroumblis had been charged and she could stare him down in court.
"I gave him a dirty look, if that helps," she said as she laughed.
Ms Bartlett's brother Martin said the families were hoping for closure after nearly 50 years.
The Easey Street home where the women were allegedly killed by Kouroumblis. (HANDOUT/PUBLIC RECORD OFFICE VICTORIA)
Kouroumblis, a dual Greek-Australian national, had been living in Greece since 2016.
Police issued an INTERPOL red notice alert but he could not be arrested in Greece due to a 20-year statute of limitation on the initiation of murder charges.
He was arrested at Rome's Leonardo Da Vinci Airport in September and an Italian judge signed off his extradition to Australia in November.
Kouroumblis was flanked by detectives as he arrived at Melbourne Airport on Tuesday night on a Qatar Airways flight.
Victoria Police Chief Commissioner Shane Patton previously described the murders as "an absolutely gruesome, horrific, frenzied homicide".
The siblings of Suzanne and Susan says they are ecstatic charges have been laid over their murders. (Con Chronis/AAP PHOTOS)
He said advances in technology, investigative techniques and retracing statements had contributed to the breakthrough in Victoria's "most serious cold case and longest cold case" ever solved.
In 2017, the force offered a $1 million reward to catch those responsible.
Ms Armstrong and Ms Bartlett were last seen alive on January 10, 1977 and their bodies were found three days later.
The women went to school together at Benalla in Victoria's north and their families have said their deaths changed many lives.
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