She was last seen alive at the Marsden State High School on October 30.
Acting Regional Crime Coordinator Detective Superintendent Mark White today announced “a vehicle of interest” has been seized.
“The vehicle will be forensically examined,” Det Supt White said.
He said the 11-month investigation had led to “a number of persons of interest”, but confirmed the owner of the car was not a suspect.
“There’s still a lot of work to be done. Today’s development is only one small step in the direction we are going.”
Police are appealing for anyone who saw the 2009 blue Ford XR6 sedan around Kerkin Road North in Pimpama to come forward.
A $250,000 reward, offered by the Queensland Government, remains in place for information which leads to the apprehension or conviction of the person responsible for Tiahleigh’s murder.
A review into the circumstances of Tiahleigh’s death earlier this year resulted in reforms for other children who go missing from out-of-home care.
It took police almost a week to release a missing persons alert under the existing protocols.
All 29 recommendations from a Queensland Family and Child Commission report were implemented.
“The report highlights that more can be done to improve whole-of-government systems and ensure more timely and co-ordinated responses for children missing from out-of-home care,” Queensland Premier Annastacia Palaszczuk said in July.
Det Supt White said there remained a “dedicated” team of detectives working on the investigation.