Police have charged the 23-year-old from Zillmere, in northern Brisbane, over the deaths of Joe and Christine Stephan, aged 73 and 68, at their Collingwood Park home on January 23.

Detectives have previously said that the couple had been killed in an “act of violence” rather than the fire.

The man has been charged with two counts of murder and the dangerous operation of a motor vehicle and is due to face Brisbane Magistrates Court on Monday

A 28-year-old Ipswich man, who police say was an associate of the dead couple, is accused of the same three crimes after being charged on January 30.

Detective Acting Superintendent Stephen Blanchfield thanked the public for their help with the investigation, but indicated it was still an open case.

Officers are currently trying to trace the movements of a black Mercedes, which was stolen from the couples home on the night of the fire.

Det Supt Blanchfield has asked for anyone with dashcam footage of Zillmere Rd, Aspley and Robinson Rd West, Geebung, between 10am and 1pm on January 22 to contact police.

“While the vehicle has been located, any information regarding its movements is of great importance to us while investigations are ongoing,” he said in a statement on Monday.

Joe and Christine Stephan, who had two adult children, were found in the lower level of the home that caught alight in the early hours of January 23.

Detective Inspector Heath McQueen said at the time they had died from significant injuries caused during an act of violence, and not as a result of the fire.

“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.