In a relaunched investigation, he agreed to provide DNA but fled Australia. It is understood a DNA sample from a relative established a match.

Attempts through diplomatic channels to have the man returned to Melbourne failed, and he was put on an international watch list that led to his arrest in Rome.

“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 Shane Patton said on Saturday.

“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. While we still have some way to go, this arrest is an important breakthrough.”

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Armstrong, 27, was stabbed 29 times, and raped. Her housemate, Bartlett, 28, was stabbed more than 50 times, with the same knife, which was never found, after coming to her friend’s aid.

Armstrong’s 16-month-old son was found unharmed in his cot.

In the statement, the women’s families said they were “forever grateful” for the support from their loved ones and police over the past 47 years.

“For two quiet families from country Victoria, it has always been impossible to comprehend the needless and violent manner in which Suzanne and Susan died,” the statement said.

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“The perseverance and dedication required to achieve the result today is something to truly behold. For always giving us hope and never giving up, we simply say, thank you.”

If you or anyone you know needs help, call Lifeline on 13 11 14, Beyond Blue on 1300 22 4636, or the National Sexual Assault, Domestic Family Violence Counselling Service on 1800RESPECT (1800 737 732).

Report information to Crime Stoppers on 1800 333 000 or submit a confidential report online at www.crimestoppersvic.com.au

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