Man arrested in Rome almost 50 years after infamous Easey Street murders in Melbourne's Collingwood

A man has been arrested in Italy over the infamous Easey Street murders in inner-city Melbourne almost 50 years ago.

A 65-year-old man, who is a dual citizen of Australia and Greece, was nabbed at an airport in Rome on Thursday night, with a charge and warrant placed for his arrest.

The arrest follows a decades-long investigation by Victoria Police's Homicide Squad, following the murders of housemates Suzanne Armstrong, 27, and Susan Bartlett, 28, who were found dead at their home in Easey Street, Collingwood on 13 January 1977.

Both women, who had last been seen alive on the evening of 10 January that year, had been stabbed multiple times.

However, Armstrong's 16-month-old son was left unharmed in his cot.

The man remains in custody, with Victoria Police now working to seek his extradition to Victoria.

A vital breakthrough after 47 years of tireless work, says chief commissioner

Victoria Police Chief Commissioner Shane Patton said the arrest was an important breakthrough, following 47 years of tireless work by Homicide Squad detectives.

In January 2017, police announced a AUD$1 million reward for information leading to the arrest and conviction of anyone responsible for the murders.

"The Easey Street murders, as they came to be known, have always been a priority for Victoria Police and an enormous amount of work has been done by many, many people to bring us to the position we are in today," Chief Commissioner Patton said.

"As well as the Homicide Squad, this includes a large number of police and staff from a range of specialist areas across the organisation. All have been wholly committed to finding answers and holding those responsible for these deaths to account.

"This was a crime that struck at the heart of our community - two women in their own home, where they should have felt their safest."

Patton said while there was still some way to go, the arrest was a crucial breakthrough.

'Enduring resilience of both families'

Armstrong's sister, Gayle, raised Gregory after his mother was killed.

Speaking in 2017, she said it was his cries that alerted the neighbours to trouble.

"He was 18-months-old, he was in the cot for two days before they found him, and it was only because of his crying that the next-door neighbour found them when they did," she said.

"I was his mum and in recent years he has found his own father and he visits them regularly and has got quite close to them, so he's going okay."

Patton said he wanted to recognise the "enduring resilience" of both the Armstrong and Bartlett families.

"No doubt this will be a very emotional time for them," he said.

"I hope this arrest brings you closer to the answers you so richly deserve and have waited so long for."

Anyone with information is urged to contact Crime Stoppers on 1800 333 000 or make a confidential report online at www.crimestoppersvic.com.au

- ABC