Maree is accused of killing her son with a smoothie 7 years ago. She still hasn’t faced trial.

New forensic evidence has been uncovered in the case of Maree Mavis Crabtree, who is accused of murdering her two adult children, and will be placed under intense scrutiny by her defence counsel.

The Gold Coast mother pleaded not guilty in January to murdering her son Jonathan by giving him an overdose of prescription drugs in a fruit smoothie in July 2017.

Her trial related solely to the death in the family's home of the 26-year-old who had a brain injury from a car crash.

Jurors were discharged after the trial was disrupted by the discovery of documents that could be admissible as evidence and Crabtree was later released on bail.

Crabtree was also committed for trial in 2021, but she is yet to stand trial for the alleged 2012 murder of her daughter Erin, aged 18.

Erin and Jonathan Crabtree. Image: Supplied.

The murder charge involving Jonathan was subject to a review in Brisbane Supreme Court on Monday, which Crabtree attended in person.

Crown prosecutor Philip McCarthy said police, after a prolonged period since Jonathan's death, had analysed the blender allegedly used by Crabtree to prepare a drug-laced smoothie.

Mr McCarthy said the forensic officer found traces of the opioid painkiller oxycodone, anti-anxiety drug diazepam and antipsychotic quetiapine.

"The presence of those items is relevant to whether or not there is any corroboration of (Tara's) allegation that her mother had placed those medications in a blender," he said.

A key witness for the prosecution has been Crabtree's daughter Tara, who claims she stood lookout while Crabtree mixed multiple drugs into the smoothie.

Crabtree's defence has previously questioned the reliability of Tara's statement and claimed it did not match other evidence.

Mr McCarthy said he would need detailed reports and forensic notes from police about how they have handled the blender since it was seized and how they reached their findings on the drugs' alleged presence.

Crabtree's solicitor said she would seek that all the police materials mentioned by Mr McCarthy were disclosed to the defence.

"I do anticipate we will seek our own expert report," she said.

Justice Peter Davis adjourned the matter until May 13 and extended Crabtree's bail.

— With AAP.

Feature Image: AAP.