Lawyers Portal

DNA in the courtroom


The courtroom needs to hear DNA evidence that is clear, simple and cogent.

Here we provide a catalogue of scientific papers and best practice guidelines which are utilised and referenced by DNA experts.

We further provide the legal practitioner with expert simple explainers for frequently heard DNA questions and concepts.

 

* This webpage content is expressly for legal practitioner  on page viewing and is not intended to represent a scientific evaluation.

We recommend that you contact Roebuck Forensics for any clarification or opinion regarding matters before the courts.

Explainers

further testing be evidenced?

YSTR

Sperm fraction

“no blood ”-“ positive presumptive”

TWO MINUTE DNA EXPLAINERS

PUBLISHED SCIENTIFIC PAPERS

TitleCategoriesLinkhf:doc_categories

Analogous to caselaw, the finer specificity of individual scientific papers in evidence should be evaluated with expertise

Notable divergence may exist between published scientific best practice and particular lab policy and procedure

SCIENTIFIC BEST PRACTICE AND GUIDELINES

TitleCategoriesLinkhf:doc_categories

LAB REPORT EXPLAINERS

Key tips:

Each Australian State and Territory lab apply differing methods of reporting DNA.

Further reporting is regularly conducted close to trial.

Lab expert opinion or weighting of the results is frequently presented orally at trial.

Brief DNA Insights

Indirect Semen Transfer

March 5, 2024

This recently published 2024 peer reviewed published scientific paper seeks to provide clarity as to the likelihood of indirect transfer of semen.

Read More »

September - 2024

Sexual assault – oral penile penetration – digital penetration – external mouth penile contact – absence of spermatozoa – oral rinse – trace DNA – social interaction

Alleged oral and vaginal penile penetration are denied whilst it is acknowledged that kissing and touching occurred. The parties were in uncontested social contact over the preceding period that evening. The allegation relies upon YSTR DNA obtained external to the mouth and DNA upon the body variously, whilst there is no DNA obtained internally or vaginally and positive saliva results exist.

The sperm fraction resultant from the differential extraction failed quantification, whilst the non-sperm fraction was subject to Y STR DNA analysis and produced an inclusionary result and likelihood ratio. Extensive testing of various samples ceased at quantification. Numerous samples were subjected to saliva testing, including the RSID test providing positive and negative results and saliva could not be reliably confirmed. Inclusionary DNA results could not be attributed to biological fluid.

August - 2024

Cold Case – Homicide – Stabbing – Crime scene officer contamination –  DNA transfer –– Complex mixed DNA profiles – Low level mixed DNA profiles –– Lab contamination – edged weapon blade geometry

A complex crime scene relying on trace DNA where officers DNA is obtained within crime scene profiles. Officers entered and exited the crime scene in proximity to the deceased before, during and after the taking of samples, when those officers duties place them in physical presence of the accused and the samples themselves.

This matter critically relies upon DNA samples which were extracted from hair and fibre samples collected in an era predating forensic DNA familiarity. An extensive crime scene records and contemporaneous notes review seeks to evaluate the possible and potential pathways for the defendant’s DNA present within the trace mixed DNA profiles taken from and adjacent to the deceased, which also bore contribution of the attending and non-attending crime scene officers and lab staff.

July - 2024

Violent group brawl – Homicide – Stabbing – Bloodstain pattern analysis – DNA transfer – edged weapon blade geometry – Complex mixed DNA profiles – Low level mixed profiles – Complex crime scene

A highly complex crime scene with multiple injured persons leading to various potential or possible blood contributions, multiple alleged assailants, multiple bladed weapons recovered and evidenced with voluminous testing and retesting of samples including complex and low-level multiple contributor mixed DNA profiles.

This complex matter seeks to methodically evaluate the crime scene factors minded towards understand the contributions of potential blood upon various weapons and moveable items related to both the crime scene itself and numerous subsequent locations. Further, DNA transfer presents as a significant consideration which is complicated further by multiple known and unknown persons within the crime scene and the potential for those individuals to have contacted persons and surfaces both before, during and after the brawl itself.

×

Lawyer’s - DNA detangled

Enter