March 3, 1982
Tweed Heads, New South Wales
Phillip (also spelled as Philip in reports) Eric Layton (21) shoots 6 members of a family and himself
Months before the shootings, Margaret Ann Ross (26) and her husband Craig (28) separated and remained estranged for 7 months. Layton and Margaret began a relationship during this time. He became jealous and angry when the Rosses reconciled and reportedly threatened to “shoot them all.” Additionally, a month before the shootings Layton targeted the tires on Craig’s car. Craig caught Layton in the act of attempting to cut the tires and Layton slashed at Craig, inflicting minor wounds.
On March 3, neighbors called police to report hearing several shots coming from the Rosses’ flat. Police entered the home through the rear entrance to find the bodies of Layton, Margaret, and Craig on the floor. Next to Layton’s body was a .223 Ruger semi-automatic rifle. Further inspection of the flat revealed the bodies of the Rosses’ four children — Petrina, 7; Natalie, 6; Clinton, 5; and Vicki Leigh, 14 months.
Investigators determined Layton had first shot Margaret with the high-powered rifle, wounding her. As she was on the floor screaming, Layton fatally shot Craig in the head. He next went into the children’s bedrooms and shot each in the head as they slept before returning to the sitting room to fatally shoot Margaret in the head as well. Layton then turned the gun on himself.

via Newspapers.com
Sources:
“Seven shot dead.” The Bulletin. March 16, 1982. Digitized: https://nla.gov.au/nla.obj-1310551288/view?sectionId=nla.obj-1602008430&partId=nla.obj-1310620728#page/n0/mode/1up
Stone, Andrew and Coultan, Mark. “Killer of family had passion for weapons.” The Sydney Morning Herald. March 5, 1982
“Mother, children hid in terror after shootings.” The Age. 5 March 1982
“Seven shot.” The Age [Melbourne, Victoria]. 4 March 1982