Police have appealled to the public for help as they try to piece together the last hours of a father and son found dead at a property in far north Queensland.
Officers found Troy Harvey's body and his unresponsive four-year-old son at a property in Rossville, north of Cairns, on Friday morning, police said on Sunday.
A 36-year-old woman had earlier contacted them to raise concerns about the pair after Mr Harvey, 45, allegedly assaulted her the night before.
Paramedics attempted to revive the boy but he and his father were declared dead at the scene.
Detective Inspector Jason Smith said investigators want to speak to anyone who had contact with Mr Harvey between August 28 and September 4.
They also want to speak to the driver of a silver vehicle who visited Mr Harvey's home on Friday morning, he said.