It has been 47 years since 16-month-old Gregory was found crying and dehydrated in his Melbourne home as his mother and their roommate lay murdered nearby.
The little boy was found distressed but unharmed as police arrived at the Easey Street rental in Collingwood on January 13, 1977, to find Suzanne Armstrong and Susan Bartlett with a combined 82 stab wounds.
The 27 and 28-year-old's were last seen three days earlier when they went over to Susan's brother's house for dinner, leaving around 9pm.
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Their neighbour across the road, Gladys Coventry, who was in her 70s at the time, remembers seeing a man with a knife in the kitchen. She watched him exit out the back lane the night of the murders.
Another neighbour recalled hearing a door slam, then two car doors slam, then a car driving off.
Officials believe that Suzanne was reading in her bed when she heard a knock on the door and let a person(s) in, suggesting she may have known him.