The prime suspect in Melbourne's unsolved Easey Street double murders in 1977 has touched down in Doha, Qatar, as he returns to Australia. Perry Kouroumblis, 65, was approved for extradition from Italy in late October.

The friends were found dead with multiple stab wounds in their home on Easey Street in Collingwood. Bartlett’s 16-month-old son Gregory was found unharmed in his cot. The 65-yea

Suzanne Armstrong (Right) and Susan Bartlett who were murdered in their home on Easey Street in Collingwood in 1977. A man has been arrested in Italy over the "Easey Street murders" of two women who were killed in Melbourne almost five decades ago. Photo: AAP/Supplied by Vic Police

A suspect in Victoria’s “most serious cold case”, the Easey St murders, has been extradited from Rome to Melbourne to face legal proceedings.

The slaying of Suzanne Armstrong and Susan Bartlett at their home in Melbourne has been described as Victoria's most brutal crime.

Dressed in a black jumper and sporting a beard, Kouroumblis sat quietly in economy class seat 35E without handcuffs, eating a meal and drinking water.

Perry Kouroumblis, who is wanted wanted over Melbourne's 1977 Easey Street murders, is expected to arrive back in the city on Tuesday evening, after being extradited from Italy.