A Queensland teenager accused of trespassing at the home of an Adelaide man allegedly murdered by his granddaughter is expected to be extradited to South Australia after failing to win bail.
Shelby Holmes, 19, fronted the Brisbane Magistrates Court on Friday as South Australian police sought her extradition to answer a charge of aggravated serious criminal trespass at the home of Robert Whitwell.
The 81-year-old's body was found at his home in Craigmore, in Adelaide's north, on August 8.
The court heard allegations Holmes went to the property roughly four months earlier with his granddaughter Brittney Dwyer, who allegedly told her the elderly man "might have to die".
Magistrate John Costello found material put forward by prosecutors suggested the teenager was involved in a "premeditated calculation" to steal from the now-deceased man with an "an element of indifference" as to how that would be achieved.
"That mindset does not provide me comfort," he said.
He said there was an unacceptable risk Holmes may interfere with witnesses that could not be addressed by bail conditions.
She was remanded in custody and ordered to be returned to South Australia.
It came after her lawyer, Michael McMillan, argued allegations relating to Mr Whitwell's alleged murder were "virtually valueless" given the charge Holmes was actually facing.
"This business about the murder needs to be put out of everyone's mind today," he told the court, which was attended by Holmes' parents.
But police prosecutor Sergeant Matt Kahler said the cases were linked because in both instances the motive was allegedly money.
The court also heard 19,000 text messages exchanged between Holmes and Dwyer over a two-year period had been recovered.
Outside court, Holmes' legal team told AAP the teenager was "pretty upset" by the magistrate's decision but there were plans to try to stop the extradition via a Supreme Court injunction application.
Dwyer and her friend Bernadette Burns were extradited from Queensland last month and charged with Mr Whitwell's murder.
