A 28-year-old Ipswich man has been charged with murder over the deaths of two people as police continue a "complex" investigation after a house fire south of Brisbane.
The couple's bodies were found in the burnt-out remains of a Collingwood Park home on January 23, with post-mortem results later showing "evidence of violence".
The man was charged with two counts of murder, one count of arson and one count of unlawful use of a vehicle on Sunday morning, Queensland police said.
Detective Inspector Heath McQueen said the man is an "associate" of the alleged victims.
Police are now looking for two motor vehicles in relation to the investigation, a green dual-cab ute and a black Mercedes Benz.
They are also seeking to speak with anyone at Kruger Shopping Village, Redbank Plains or Hannant St, Collingwood Park on the morning of January 22.
The couple - who have been identified by colleagues on social media as Joe and Christine Stephan - were found in the lower level of the home that caught alight early last Sunday.
"We have identified that Joe and Christine died from significant injuries caused during an act of violence, and not as a result of the fires," Det Insp McQueen said on Sunday.
The couple had two children, and police are working with the family to provide support and welfare as the investigation proceeds.
On Friday, Det Insp McQueen described the circumstances of the house fire and deaths of the 68-year-old woman and 73-year-old man as complex.
"Post-mortems have been conducted ... I am unable to go into details other than confirming their deaths are suspicious, and not contributable to the fire, with evidence of violence," he said.
The 28-year-old is due to front Ipswich Magistrates Court on Monday.
© AAP 2022